TheSamba.com :: View topic - Subarugears 4.868 Ring & Pinion

Fri Jun 17, 2016 4:32 pm

I’ve decided to assemble a photo series of my reversed ring & pinion setup from Subarugears as I anticipate there are many others out there whose projects will halt once they reach the step regarding setting up the ring & pinion gear mesh. I have not found any sufficient resource online that speaks directly to the real-life setup concerning this step. Though Subarugears and others here on the samba have done this step, I have felt that the level of detail specific to this phase has not been at the granularity I had hoped for. Seeking a sort of “mesh-map” that is more than just an artistic rendition of general case examples good and bad, I’ve decided to assemble one with photos sourced from my specific trials and tribulations.

For starters, here is a bit of background on my situation and how I arrived at my decision to go with the Subaru 5MT as my gearbox of choice:

First and foremost, perhaps I am a bit more neurotic regarding the gear mesh as my Vanagon has a history of eating gearboxes. Be it the appetite of the EG33 Subaru SVX power plant, the lead-weightedness of my right foot, or the alluring roar of the Boxer H6 when this combination comes together… big smiles happen, that is until something else in the transaxle gives up and brings the beastly camper to its knees. First it was a matter of sheering all of the teeth off of 4th gear (in the original aircooled gearbox)… then it was grinding the teeth away from the ring and pinion of the 094 late model, Rancho-built gearbox (evidently due to the pinion nut backing off and allowing excessive slack/backlash, which they so kindly replaced)… now, I cannot tell for sure as I haven’t opened it up yet for fear of what I may find (on the newest Rancho-built replacement gearbox).

Disclaimer: Don’t let me give you the wrong idea of Rancho Performance Transaxles… their staff has gone above and beyond for me in taking care to replace my damaged gearboxes, despite my non-stock drivetrain configuration (which they are/were aware of). Their R&D department has used cases like mine to refine their builds so that others in the future will benefit from beefier parts of identified weak points, inhibiting potential failure.

Regardless, the time and money investment in gearboxes has been much greater than anticipated. So, for any of you who are toying with the idea of a Boxer H6 in your Vanagon, consider yourselves warned. Yes, it will be most excellent being able to pass virtually everything on the road in your brick-mobile, though there will be many other necessary (and costly) upgrades required to keep you safe from the vehicle’s Jeckle & Hyde esque mood swings (ie: brakes/suspension/bushings) as well as keeping the vehicle safe from itself (ie: transaxle upgrade).

With that said, my Vanagon had noticeably large gear gaps in the latest 094 gearbox, so great time and effort was spent selecting the ideal gearbox and gear ratios when I had decided to go with the Subarugears Reversed Ring & Pinion kit.

My previous setup consisted of a factory Vanagon 1st -2nd, with Weddle 3rd-4th and the 4.868 Ring & Pinion, turning 225/75/16 series tires (~29” diameter).
Here are the particulars regarding the ratios (for the gear heads out there):
1st – 3.78
2nd – 2.06
3rd – 1.14
4th – .70
R&P – 4.868

Overlaying the previous air-cooled configuration (with 27" diameter tires and 4.57 Ring and Pinion) with the 094 Rancho upgrade (with 29" tires and 4.868 Ring and Pinion) looks like this:

Though these gears might have been ok for a Vanagon with a tire diameter up to about 27”, they were not ideal once I hit the hills as 4th was way too tall and the gap was excessive between 3rd and 4th despite the hefty power gain from the SVX H6.

After much scrutiny, I’d arrived at the JDM Turbo Forester Gearbox of the model year 1999-2000 range (transaxle code TY55VB1AA). This gearbox was built to handle the power of the WRX/Turbo Forester so it should be able to take the power of the SVX without compromising its integrity. This gearbox was also ideal as it has the male differential output shafts which are much easier to adapt the Subarugears axle flanges without having to purchase stub shaft adapters separately. Unless you're looking to upgrade the differential right out the gates, this is a cost saving point to consider. The TY55VB1AA ratios look a little something like this:
1st – 3.454
2nd – 1.947
3rd – 1.366
4th – .972
5th – 0.738
R&P – 4.868

Overlaying the previous 094 Rancho configuration with the Subaru 5MT upgrade looks like this:

For my purposes, these ratios were ideal. I kept 1st and 2nd within 2mph of the stock Vanagon gears @ 4k RPM meaning I will notice very little (if any) difference in gearing while out exploring forest roads. 3rd and 4th will be the largest improvement over the previous setup as the Vanagon would previously be turning about 63MPH @ 4k in 3rd, with the Subaru Gearbox it’ll be about 52MPH in 3rd and just shy of 74MPH in 4th, so my relative gearing gain is essentially +/- 11MPH @ 4k RPM on either side of the previous 3rd ratio. I believe this will give me optimal range when I am traveling the mountain highways as 3rd was previously too short for highway travel (revs were too high) and 4th was too tall. Just as Goldilocks found with the 3rd bowl of porridge, this combo should be juuuust right. As I found 5th to be a bit on the tall side, compromising with a .738 5th should bode nicely with the overall gearing in this configuration.

Now that you’ve been primed with the background of my situation, let’s get into the task at hand.

I don’t plan to go into detail regarding the required case modifications as they are pretty well documented already and are a sort of trial-and-error type deal. Once you’ve flipped the diff, you’ll be able to see where contact is being made. At that point, grind the contact points, recheck clearance, grind the contact points, re-check clearance, and so on. Subarugears documents that bit of work here (http://www.subarugears.com/Casing/Casing.html). I’ve found that applying a thin layer of gear paint to the surfaces that are not immediately identifiable once the majority of clearance has been made will help to highlight the contact points as they will be shining bright in contrast with the paint. Just my $.02 on that note.

Specifically, once the case is clear, the ring gear is installed on the diff and the pinion shaft is installed within the output gear stack, we will arrive at my major point of conflict. At this stage of the install, one would hope everything should magically fall into place… A bit of wishfull thinking? Possibly. Reality however often times proves to be a harsh mistress, rivaling figures of demon lore.

Following the protocol described in the assembly video on the Subarugears site (http://www.subarugears.com/Assembly/Assembly.html), I first measured my pinion depth with ZERO shims to see approximately how many tenths of a millimeter worth of shims would be required to bring my pinion depth to the ideal of ZERO. Well, for starters, my pinion depth gauge (as provided by Subarugears in their install kit) didn’t quite fit in the alignment holes as perfectly as I think they should have. The dowels of the gauge were just a bit out of phase and required a bit of persuasion (a la ball-pin hammer) to get the dowels to seat into the case half. Once “installed”, there was a slight upward bow in the gauge that made the center read point out of plane with the case half. To take my reading, I lightly pressed the center of the plastic behind the read point to bring it back to the plane of the case halves. Once it was as close as feasibly possible to flush, I slid the “dial indicator” between the “read point” and the pinion head to determine the required pinion shim thickness. Due to the bowing of the gauge, my readings were anywhere between .7mm and .9mm at any given moment when measuring with ZERO shims, so there was a bit of range to the determining of the initial starting point for the pinion depth on this project.

My gearbox was delivered with a factory shim assortment of approx. .63mm, I needed to place an order for more shims that could get me to get me to the upper end of my ballpark measurement of .9mm. I ordered up a few shims, 2x of the 32295AA091 (.300mm) variety and 1x of the 32295AA071 (.250mm) variety. Since Subarugears advises that most cases would need about .45mm-.50mm of shims to zero out the pinion gear, I erred on the lesser side of .9mm as I figured my wonky pinion depth measurement likely was not telling me the whole truth. With the pinion depth gauge’s range of 0.00mm-1.00mm, .9mm seemed excessive to me, but at that point, I was not at liberty to challenge the gauge.

Once the new shims arrived, I jumped to start the assembly process. In went the fresh shims at .85mm (actually reading closer to .83mm with my micrometer), then the pinion gear gets dropped in and aligned with the pinion bearing dowel and bolted in place via the pinion keeper bearing/plate on the pinion shaft opposite the pinion geared. NOTE: After the many installations you’ll soon read about, I had stopped installing the input shaft despite instruction to do so as I had felt that it offered no benefit at this point of the install and only added additional time and work to the process.
Lots of momentum at this point; All is good in the neighborhood.

Next, I flipped the bearing races from one side to the other (this keeps them associated with their original bearing races [post diff reversal], I also have learned to turn-in the diff cup of this case half so that there is excessive backlash to start with [reasons will soon unfold]),
Then we drop the differential with the reversed ring gear down into the bearing race and into the spiral of the pinion gear… Ah-yeah, gear cog lovin’.
Now, we’ll back the diff cup off of the other case half (the half clearanced for the ring gear reversal) so that there is no preload on the differential bearings. Install the case half and bolt in place, snugly-tight. Boom. Movin’. Now time to adjust the backlash…

Instead of flipping the transaxle over to the opposite side as the factory documentation suggests, it is much easier to leave it in the orientation it was upon assembly for the next adjustment. Doing so will allow for us to drop the differential unit down into the spiral of the pinion gear via gravity as opposed to pushing it up into the spiral as we would if we were to follow the instructions verbatim. (9.81 points for working with the G-force!)

It didn’t occur to me at first that the nature of this ring and pinion reversal would imply most of the instructions would, in fact, need to be translated into the exact opposite of what the text/graphics are saying. Keyword: MOST (but not all), so don’t get too ambitious with reading into the opposites. This adds another layer of “FUN” to the process… a sort of ENIGMA machine (https://en.wikipedia.org/wiki/Enigma_machine) requiring a collection of the sharpest minds of England to decypher. Well, maybe it was not that involved, though the varying degree of opposites in this exercise are far from straight forward.

So, we’re dropping the differential/ring gear down into the hypoid spiral of the pinion gear by turning the cup on the bottom side of the case (side opposite the ring gear) counter-clockwise while we are turning the pinion gear by hand, feeling for a slight resistance in the input shaft, at which point we’ve reached the ZERO depth or ZERO backlash point. While enroute to the ZERO depth point, I tend to hand tighten the cup on the top side (ring gear side) of the case to relieve the slack in the differential bearings created from our diff-drop practice. This helps to keep the differential unit perpendicular to the pinion shaft as we approach the ZERO depth point.

The ZERO point approaches very quickly once evident. I’ve found that there is little effort required in turning the pinion shaft for most of the diff-drop phase, then a slight turn of the bearing cup in the drop direction (say .5-1 tooth worth) and a slight resistance is felt, then another slight turn of the bearing cup in the drop direction (another .5-1 tooth worth) and now the pinion shaft is bound by the ring gear and nothing wants to turn with ease. At this point, back the ring gear out to the point where slight resistance is felt, take any slack out of the ring gear side bearing cup and we’re ready to move on to the next step.

On the ring gear side, back the diff bearing cup off 1.5 teeth. (NOTE: the bearing cup lock plates are adjustable to the .5 tooth level by flipping the lock plate to its other side. Quite nifty little buggers.)
Opposite the ring gear side, tighten the bearing cup 1.5 teeth. At this point, the backlash SHOULD be within the acceptable range. Finally, tighten the bearing cup opposite the ring gear side of the differential an additional 1 tooth to set the differential bearing preload.

I’ve tried to use the damn dial gauge as called for at this point, though the service document suggests to take the reading off of the ring gear teeth through the drain plug hole (a practice no longer valid with the ring gear reversal as it is no longer in-line with the drain plug hole). The suggested read range on the gauge is in the realm of .13mm to .18mm or .0051” to .0071”. These are the values specified by taking the measurement from the RING GEAR… which we’ve determined we can no longer do as a result of ring gear flipage.

Let’s get into some maths… assuming that the ring gear has a diameter of approx. 7” (for the sake of illustration as I do not have the ring gear in front of me at this time for hard measure), that generates a radius of 3.5”. No surprises there. Now, since the ring gear’s outer diameter is where we are supposed to be taking our backlash measurement, whatever the resulting read returns is a measure of the ARC LENGTH (or as in our case, the BACKLASH) on that outer edge of the ring gear circle.

For the curious and/or an ARC LENGTH concept refresher: http://regentsprep.org/Regents/math/algtrig/ATM1/arclengthlesson.htm

Knowing our radius to be 3.5” and our target ARC LENGTH (or BACKLASH) reading to fall within the range of .0051” to .0071”, we can determine the inner angle range responsible for rendering the desired ARC LENGH range using a simple formula:
RADIAN MEASURE (inner angle) = ARC LENGTH (or BACKLASH) / RADIUS (of ring gear)

So, then RADIAN MEASURE (lower extreme) = .0051”/ 3.5” = .00146 radians
And, RADIAN MEASURE (upper extreme) = .0071” / 3.5” = .00203 radians

These are the EXTREMES of the relative inner angle with respect to the ½ the DIAMETER measure (the RADIUS) of the ring gear. The Subarugears set up video suggests that the same BACKLASH range be taken from the splines (or the pinion nut) of the pinion shaft, however the relative diameter of the pinion shaft to the ring gear is DRAMATIC! We’re talking 1” versus about 7” here. There’s no way that the backlash reading taking at a 1” diameter is going to be the same as that taken at a 7” diameter, because… SCIENCE! (well, Mathematics rather… but I digress.)

Rearranging our formula a bit, we can solve for what the ARC LENGTH (Backlash) should be when taken on a diameter of 1”.

RADIAN MEASURE (inner angle) = ARC LENGTH (or BACKLASH) / RADIUS (of pinion shaft)

Multiply both sides by the radius and we have:
RADIUS (of pinion shaft) x RADIAN MEASURE (inner angle) = ARC LENGTH (or BACKLASH)

And pivot the formula around the “=” sign:
ARC LENGTH (or BACKLASH) = RADIUS (of pinion shaft) x RADIAN MEASURE (inner angle)

Inputting our known angle values from above:
ARC LENGTH (or BACKLASH) = .5” x RADIAN MEASURE (inner angle)
ARC LENGTH (or BACKLASH lower extreme) = .5” x .00146 radians = .00073”
ARC LENGTH (or BACKLASH upper extreme) = .5” x .00203 radians = .00102”

As you can see, a BACKLASH range of .00073” to .00102” is HUGELY different than a BACKLASH range of .0051” to .0071”, like a 7x level of hugely different!! At this point, I decided that dealing with measuring the backlash was going to conflict with the Subarugears’ suggested practice and by following the suggested protocol, I’d likely be running into trouble down the line, as following the suggested route will put me dramatically out-of-spec, far more than if I were to do it by feel following the factory documentation minus the now impossible to do ring gear backlash measure. Having such a sour past with Ring and Pinion failures, I do not want to risk destroying a part that costs $1.5K due to procedural oversight. Unfortunately, it seems that everyone has been following this practice in their DIY setups… Hopefully this article will inspire a refresh and/or detailed documentation explaining this step a bit better for others out there who are eager to use their product.

At any rate, I’ve elected to run this course in backlash adjustment by feel as it seems that the reads I’ve been getting from the contact pattern (as viewed in later steps) suggest that my backlash hasn’t been obscure. Moving right along now… Everything has been assembled, and the pinion depth and backlash have been reset to one another, guess what we get to do?? We get to take everything apart again!!

This time, we will not alter any of our currently defined settings as we are going to check those settings by reading the contact mesh pattern. To do so, we will paint about 3-4 gear teeth every quarter turn of the ring gear with special gear paint. At first, I used the Dykem “Steel Blue” machinist paint, though I found that the film was too thin and it was quite difficult to decipher the contact pattern with this medium as it was relatively transparent and had inconsistencies with thickness across the gear teeth. Now, I’m using the Richmond Gear Paint available through Summit Racing for less than $10 for what can easily be a lifetime supply for those who don’t intend on rebuilding gearboxes anytime in the foreseeable future. I think it would be a nice addition for future releases of the Subarugears Ring and Pinion kits to include a bit of gear paint as I’d easily spent an additional $20 between the Dykem and Richmond Gear paint trying to track down the best product (and now I’m left with way more than I need). A sample about the size of a hot-sauce/ketchup/mustard/mayo/etc. packet would be plenty for the DIY job and one less thing to track down for the DIYers once their kit is in hand... Just a thought.

With the quarters of the ring gear painted up, we are ready to re-assemble the transaxle.

Now that everything is back together, we’ll spin the input shaft both clockwise, then counter-clockwise enough times for the differential/ring gear assembly to make a few good full revolutions in each direction. This method, however applies a relatively minimal load on the contact point between the gears. To combat this, I also recommend spinning the output splines from the differential a few full cycles in both directions as this effectively multiplies the load we’d administered through turning the input shaft by a factor of the given ring and pinion ratio (in my case 4.868 times the load). This helps to simulate the effects of the transaxle being loaded by the forces exerted on the gear tooth contact patch under normal, in-vehicle operation, which in turn gives a more accurate/dynamic gear mesh smear pattern on the gear teeth.

After your forearms have had themselves a solid workout and the gears have been substantially cycled, guess what we get to do (you might be seeing a trend by this point)… that’s right, take it all apart again!! Horray for redundancy!! Pardon my sarcasm here… you have to understand that I’ve done this now more times than I can count and it is very well to the point that I can (and am currently) doing these steps over and over again in my sleep. In all fairness, this step is necessary and will surely be repeated at least a handful more times in the event that you are lucky and arrive at the ideal mesh pattern sooner than I did, which is what this whole article aims to foster in the first place. If it can help anyone save time on their build/assembly, then I’ll chalk this discussion up as a success. I’ve spent countless hours assembling, disassembling and reassembling this gearbox when I had initially expected it to be quick and rather painless process (as the assembly video and other Samba threads seemed to suggest). Having already converted my Aircooled ‘81 Vanagon to Watercooled Subaru SVX power, modified the ECU wiring harness, rewired the entire vehicle with a late model harness, converted to a late model transaxle and shift linkage, and upgraded nearly everything underneath the Vanagon involving brakes/steering/suspension myself (and occasionally with the help of friends)… I was entirely surprised when the reality that this upgrade ended up causing me the most grief of all. At any rate, where were we… oh yes, rinse and repeat.

Upon disassembly, you might see a contact wear pattern that looks something like one of the combinations on the chart below:

As you can see, I’ve run through this gauntlet of gears quite a few times now… In this latest cycle, I’ve been taking photos of the patterns at approximately .2mm pinion shim adjustment intervals. As I approached the “Ideal”, I realized that a chart like the one above would have been hugely helpful by expediting my assembly by giving both a target and a relative map to get there. I now figure that after the initial gear mesh read, I’d likely need only 3-5 more assembly cycles to arrive at what we could categorize as the “best” mesh pattern available while working in the finite 0.0mm-1.0mm (or so) realm of adjustment. My hope is that someone out there could run through their initial adjustment, match up their pattern to the chart, then adjust their pinion depth accordingly by adding or subtracting the approximate shim difference from their initial gear mesh reading to one on the chart that is more ideal without having to go through the insane amount of assembly cycles that I have thus far. Then again, if nobody sees the value in this gear mesh lookup table, that’s fine… I know now that it will be of tremendous help for me in the event that I end up doing another Subaru 5mt assembly in the future.

Unfortunately, despite my arduous efforts, I still do not feel that I have arrived at an acceptable gear mesh pattern for this Ring & Pinion gearset.

Comparing to the factory-spec illustrations:

And to a very helpful YouTube explanation of the mesh pattern cause and effect relationship:

…I am not convinced that I have arrived at the correct pattern, though at this point, I am unsure of what to do short of machining the shimmed side of the transaxle case down to permit additional pinion depth since my readings have never indicated that I've arrived at a point anywhere near "too deep". It appears that the measure of .00mm has the best read on the COAST side, though the DRIVE side is still suggesting that the pinion shim is too thick... Well, with zero shims in the picture, how this is possible is beyond me. I cannot tell if my transmission case is defective, the Subarugears Reversed Ring & Pinion is defective, or if my ability to understand/implement/follow directions is defective. All I know is that my project has now been stalled out and I've been not been able to make sufficient progress since February of this year. My hope is that this thread will generate a discussion about this insufficiently documented step and hopefully bring in thoughts and opinions from those of you who have either installed the Subarugears 5mt Reversed Ring and Pinion in your Subaru transaxles, those with experience setting up ring and pinions and/or those of you looking to take this route for a transaxle replacement. Any input will be greatly appreciated. Cheers!

Sat Jun 18, 2016 9:42 am

Talk about déjà vu! I went through all of this same confusion and frustration when I did my reverse gear installation. Kudos to you for being able to document it so clearly. I came to the same conclusion; that paint rub marks are the only trustworthy way to confirm the correct R&P alignment. After countless assemblies and disassemblies I expressed my concerns to Todd at Subarugears and he replied with this:

Quote: The first thing you need to be aware of is that the flipped ring and pinion drives on the coast side do to the reversed cut of the gears. So the most important thing is to have a good setting on the coast side rather than the drive side. (Just to be sure we are all on the same page, by coast side I mean the longer side of each gear.)

We tend to find that we get a good pattern at 0.5mm but anywhere from 0.4mm to 0.6mm is where most of them fall into. From your information it seems your best pattern and nice wide spread on the coast side is around 0.5mm of shims so I recommend you set it close to that.

With the backlash, we set it at 0.15mm measured from the splines on the end of the pinion. We have used this method for a few years now after trying different settings and different tools, installing transmissions into cars and listening to them on-power and off-power, then adjusting in and out. Whilst there is some angular difference in having a dial gauge on the ring gear (larger) and having the dial gauge on the pinion (smaller), the difference in practice was negligible. Measuring at the end of the pinion gives a consistent reading rather than trying to make a tool to reach around angles through the case hole and across to the ring gear. This was too inconsistent for our liking.

I hope this gives you the information you require to confidently set your gearset up.

kind regards

Todd Triebler

His information put my mind at ease and I decided that maybe I was over-thinking this. I held my breath and did one final assembly and moved ahead with the installation. Maybe I just got lucky, but after 4K miles everything seems OK--meaning there is no whine on acceleration or deceleration. I admit that I have not yet drained the oil to see if something is getting chewed up. Someday I will get brave enough. In the meantime, I'm happy to be using my Camper for what it was intended. I guess somewhere down the road, I could realize I made an expensive mistake, but after watching the video on the Subarugears website, and seeing how they set-up the R&P, I'm thinking that I was more careful than they are.

Good Luck,
Cameron

Sat Jun 18, 2016 10:23 am

This is one WICKED post. Huge effort and I'm sure members are thankful. Awesome find on YouTube, thank you.

wcdennis wrote: I have not yet drained the oil to see if something is getting chewed up. Someday I will get brave enough.

I would check it. You can attach a shop-vac to the filler and remove the drain magnet to inspect. It doesn't take much vacuum to keep the oil from coming out, especially if its cold. Not even a drop comes out. If your vacuum has a leak/throttle opening you will need that, as full vacuum could be so much it sucks oil spray into your hose. Or duct tape a smaller hose to the big hose, leaving a pretty substantial 'leak'.

Other way is to simply change the oil and be sure - then you have clean oil too.

Sat Jun 18, 2016 12:23 pm

Good post. Yes, taking a pattern is the only way to go, imo. I must have had the box apart/together about 30 times. Fwiw, I didn't have much luck with the supplied pinion depth gauge. I built the box adding and subtracting shims and finally settled on 0.25mm closer than the plastic gauge had indicated. I sent pictures to Todd and asked his advice and he graciously and promptly replied.

Tbh, my gearbox is slightly noisy on decel, but mostly only noticeable to myself and other trained people. No one else I've had in the van has commented on this. I think mostly it's just me being overly sensitive. Regardless, I try to stay off it and coast as much as possible, which I feel is advisable anyway regardless of gearbox. Brakes are cheaper and easier to replace. Under acceleration the box is as quiet as a mouse in slippers. After 10K miles I'm not too terribly worried about it. I figured if it wanted to blow up it would have done so by now. At this point it's simply keeping track of the fluid and watching for any changes. On that note, I'll second the recommendation for changing early. In fact, I'd suggest maybe 500 miles and then a dump for fresh fluid. This will get the break-in oil out as well as any dust, etc. that may have collected while the case was open.

-Kevin

Sat Jun 18, 2016 4:40 pm

This is a great post! I know how frustrating it can be trying to get the mesh pattern set up to a point where you are comfortable with it.

I've been working on some additional tools and procedures which I will be documenting/videoing/releasing soon in order to try and make the process a little less scary.

Having had the email discussion about this project yesterday, I will be sending another 4.86 ring and pinion plus pinion depth gauge out to Carl. I think the project has sat on the bench long enough and we want a result! It's a significant investment and you don't want it to go wrong.

This new 4.86 is a "2WD only" design which improves upon our existing "2WD/AWD design". Let's see how the mesh pattern comes up on this one.

Sun Jun 19, 2016 6:14 am

I hear ya on the paranoia about destroying another tranny. I too have an 3.3 and have been struggling to keep trannys alive. I did get about 6k Kms on my 5MT tranny though prior to its demise. I busted 1st gear in which in turn resulted in the bearing area on my SubaruGears pinion shaft wearing down. I was looking forward to cracking the case to inspect the R&P, never mind the gears I knew were broken, I wanted to check out my R&P and see if my backlash had anything to do with 1st gear getting broken.

I was pleasantly surprised that the R&P gears were still intact. I did drive the van hard and I though for sure there would be busted teeth on the R&P but there wasn't. There was some small marks on the face of some of the teeth that I was going to try and polish out but I didn't have too since the pinion shaft was finished. I assume that the imperfections on the face of the gears was from the metal that was floating around in the oil and not an improper backlash set up, but who knows for sure?

Although I "think" I could set the backlash again, I didn't like the uncertainty every time I drove the van. Maybe I got lucky the first time, who knows. I just don't have enough experience setting backlash.

I ordered another R&P.....sigh$$ but what do you do? I got another pair of gear stacks from the wrecker and will be assembling another tranny next month when I get some time. I'll tell ya, its a whole bunch easier doing it a second time around. All the hard work is done, I'm reusing the case and tail end.

I stopped by a local tranny shop and they said they can set up the backlash for about 1-1 1/2 hours of labour so, as much as I hate paying for labour, I think I'm going to go that route. Unless of course, as Todd mentions above, the new docs, videos etc. will be ready in time for my second assembly.

On side note. I was very impressed the 5MT tranny and the increased fuel mileage with the 3.9 gears. Also, Todd's customer support was outstanding and he was able to answer the many questions I had during my first build.

Maybe this time around since my wallet isn't as heavy as my right foot I might stop doing brake stands at the lights before I launch :lol: (The 5mt sure wakes up the Ol' van)

Jon H.

Sun Jun 19, 2016 6:58 am

Thanks for the kind words Jon. We really do our best to provide you a great quality product and decent customer support.

The new ring and pinion you ordered is shipping out this week - it is also our new "2WD only" design which has a number of design improvements but is also of a higher spec material, our own forging and has been shotpeened for stress relief. I hope you enjoy the product and thrashing your van even more now.

Sun Jun 19, 2016 10:17 am

Thank you all for chiming in on the post! I feel much better knowing that others have experienced the same sort of issues regarding the Ring & Pinion setup. Furthermore, I feel lightyears better knowing that Todd and company over at Subarugears have taken the initiative to address these concerns with an additional improved version 2 of the 4.868 gear set. I can not stress enough the quality of their business and the prompt responses I've received to my many inquiries throughout this project. At this point, I am also eager to install the "2wd-Only" version and put together another gear mesh chart as I think it will be tremendously helpful for a first timer setting up their Ring & Pinion. Having a real-life example of (relatively) equally spaced pinion depth intervals should help to quickly determine how many +/- millimeters of shims will need to be added/removed to get into the ballpark of the ideal.

Mon Jun 20, 2016 3:16 am

Hi Carl,
I re-read your first post (there's lots to take in) and wanted to give you some feedback on your backlash measurement and radian mathematics.

Subaru requires you to measure the backlash of 0.13-0.18mm at the edge of the crownwheel tooth. The key here is to realise that you are measuring the in/out distance between the mesh surfaces, which is in the centre of the teeth of the ring gear/pinion and you are measuring that from a few mm away of the mesh, at the outer edge of the teeth. It's easy to think that you are measuring lateral movement of the ring gear from the centre to the outside edge but it can get things confused.

This is especially so, when you then translate it to having a stationary ring gear and a moveable pinion as per our reversed ring and pinion. You might think you need to measure the backlash at a distance from the pinion centre the same as what the ring gear outer distance is (around 3 or so inches). I did the experiment just to prove to myself that this was false.

I created a "backlash measuring tool" that fits onto the pinion threads and is held down by the pinion nut. It has a flat edge from the centre line out to the distance of the ring gear diameter.

Measuring with a dial gauge at the outer edge, you get a backlash of 1mm...far too much.

I repeated this on a number of factory Subaru transmissions, turbo and non turbo to ensure it was consistent. 0.9mm to 1.0mm every time.

As the dial gauge gets closer to the pinion centre, the measurement gets closer and closer to the desired specification. I measured it at the inner end of the flat edge and got a backlash measurement of 0.24mm. Better but still not accurate.

Makes sense when you see it on the video, but the theory and mathematics can get messed up in your head.

Finally, measuring with the dial gauge onto the pinion splines gave the desired result of 0.13 to 0.18mm backlash on 3 transmissions in a row.

I will make a new version of the backlash measuring tool with the flat end further in (same diameter as the splines) so that it is easy to locate the dial gauge pin onto a flat surface. Measuring at this point will ensure everyone sets their backlash to specification with a minimum of fuss. These will go into every kit. Hopefully that helps the process!

Thu Jun 23, 2016 5:25 pm

Here's the new version of the backlash tool which provides a flat surface for your dial gauge pin to sit at the correct distance to measure 0.13 to 0.18mm backlash. I have a number of them 3D printed in sturdy plastic for now until I can get the laser cut metal ones done.

We set up a new 2WD Hi Power 4.86 ring and pinion this morning using this tool and a nice straight pinion depth tool.

To get the pinion depth to zero out we used 0.56mm of shims on the driven gears.

We measured the backlash at 0.13mm using the above tool.

Drive side ring gear pattern slightly towards toe as per Subaru manual :

Coast side ring gear pattern centered, perhaps a touch towards heel.

I will be dispatching one of these gearsets, a new pinion depth tool and a new backlash tool to you today. I look forward to seeing your results!

Mon Jun 27, 2016 7:58 pm

Excellent! Thank you for lending so much support and insight Todd. I agree, these patterns look much better than the ones I was getting… I'm getting pretty anxious now anticipating the delivery of the new R&P and it is looking like it'll be arriving tomorrow!! Unfortunately I will not be able to dive into the next phase of the mesh maps until a little over a week from now.

Just to make sure I'm understanding your explanation of the backlash, I'll roughly paraphrase your words to ensure my brain gears are in sync. For a sanity check, you measured at approx. the ring gear radius (roughly 3") and got a measure of 1.0mm. Comparing to the Subaru factory spec at the 3" radius, you also got a measure in the same ballpark of .9mm-1.0mm. Since your measure against the factory spec at the same radius of 3" renders the same backlash measure, measurements taken at the same radius will continue to scale equally with the radius measure point. Subaru specifies a measure of .13mm-.18mm backlash and your testing has indicated this range arrives when measuring the backlash at the splines of the pinion shaft. As your measured radius approaches the direction of the splines on the pinion shaft, the resulting measure approaches the target range. When you measured at the pinion splines, you are dead on target. Is this measure point the target because it most closely approximates the radius of the pinion gear's root radius (allowing us to obtain a measure of the actual gear movement between the drive/coast contact points)? I might be over extrapolating here, though I'm trying to put it in terms that make sense to me. This explanation of measuring at the pinion spline registers as reasonable, though please correct me if I am misinterpreting something here.

Also, with all things considered, wouldn't we be getting a more accurate reading by taking our measure at your 3" radius point and an aim for 0.9mm-1.0mm backlash from that point? A larger radius would give better resolution on the measurement as opposed to measuring at the smaller radius. Though the window between 0.9mm-1.0mm is 2x larger than the window between 0.13mm-0.18mm, seeing that the factory setup registered in this range suggests that measuring at this point might not be a bad idea if we were to adjust the target point with the measured radius. Doing so gives us double the resolution to shoot for when measuring at the increased 3" radius.

Thank you for posting the release video for the updated Ring & Pinion design. The improvements you have taken into account should render a vastly superior product. Reading the various responses on your Facebook post, especially from one of your beta testers with a history of exceeding the limits of previous designs, really gave me a confidence boost for the durability of the revised product. For those who haven't had a chance to see the improvements of the 2wd Hi Power Ring & Pinion, check out the video:

Tue Jun 28, 2016 1:46 am

Hi Carl,

Thanks for your feedback. IMHO you are totally overthinking it and making it harder than it can be.

Subaru does not specify a backlash of 1mm at roughly 3" radius because you are not measuring how far the crownwheel turns with reference to the center.

They specify a backlash of 0.13 - 0.18mm at the 3" radius with reference to the pinion mesh.

It is a different set of mathematics.

Why you would want to try and find "double the resolution" is beyond me, when the factory gives quite a reasonable range and builds hundreds of thousands of these every year. It's just not necessary. Gear mesh is not a perfect science, it's setting it up to within an "acceptable range" and "acceptable pattern". Please understand I say this with respect, as I know you want to get a really good result and I appreciate your thinking about it and documenting it.

When you receive the package, please try it with the tools that I have developed and let's see if you can easily set the backlash within range and generate a nice pattern. If that proves to be unacceptable then let's entertain additional options :-)

Tue Jun 28, 2016 7:50 am

No worries Todd, I am simply attempting to grasp the science of hypoid gears… It appears that the key point of understanding is reference to the pinion mesh at the pinion head.

I intend to proceed with the process as documented as I both understand and agree that the purpose of getting the backlash within the specified range is aimed at putting us well within the ballpark of acceptable. The mesh pattern is key and will be unique in each instance depending on ones particular transmission case (requiring anywhere between 0.00mm-1.00mm of pinion shims as well as a considerable range of adjustable backlash). The setup suggestions as per the calibrated pinion depth tool and the backlash tool should render significant clarity in obtaining the "acceptable range"/"acceptable pattern" with minimized effort.

Out of curiosity, have you sampled the factory procedure on a factory gearbox (taking measure through the drain plug hole from the ring gear) in conjunction with the measurements taken at the pinion splines from the same factory setup? I'm sure you have and I only ask this as I think it would put the final nail in the coffin regarding the backlash discussion. Subaru suggests that a measure at this reference point should hit the acceptable backlash ballpark of 0.13mm-0.18mm. You've illustrated that both the factory setup and the Subarugears reversed setup are equal at the 3" pinion spline measurement with an equivalent range of 0.9mm-1.0mm, and you've shown that this translates to 0.13mm-0.18mm at the pinion gear splines. Assuming all things equal (due to the common measurements described above, taken between the factory and the Subarugears setups), I would suppose that were you to take a measure against the Subaru factory setup, you would get a return measure somewhere in the realm of the 0.13mm-0.18mm range. One could compare the resulting measures at both the ring gear and the pinion splines on the factory Subaru setup to verify their respective relationship (perhaps you've already done this and is why Subarugears specifies taking measure at the pinion splines). From my perspective, knowing that the ring gear measurement of these equivalent scenarios renders parallel results, linking the factory specified measure taken at the ring gear to the Subarugears specified measure taken at the pinion splines would 100% validate the accuracy and the justification of taking the measure from this alternate point of measure as the physics of the ring gear reversal does not permit utilizing the Subaru factory procedure.

Know that I sincerely appreciate your support in this effort… big points for customer relations and customer satisfaction to Subarugears!!

Tue Jun 28, 2016 8:33 am

Yes we did :D

Sun Jul 17, 2016 3:40 am

C'mon guys - a month since the first post, I get nice replacements and upgrades out to you pronto and now updates for nearly 3 weeks?

Let's not leave this thread hanging - I'd love to see your progress with these setups and see your rigs rolling :-)

Mon Aug 01, 2016 6:51 pm

Well I finally got the tranny built last weekend using the new and improved subarugears ring and pinion-3.93s. Since this was my second 5mt build there are some differences since my first build a few years ago. The main difference was that the new ring and pinion doesn't look the same as a stock one. This caused a bit of a panic when I went to assemble the stack. Also, this time the pinion shaft has to be pressed in using a shop press. Don't press it all the way in at first. You have to line up the splines on the pinion shaft and the gear stack with the suba spool. I pressed the pinion shaft in until the the splines on the suba spool made contact with both the pinion shaft splines and the gear stack splines. I then put a homemade (made during my first build) tool in the vice which holds the pinion shaft at the spline end and used a pipe wrench on the big nut on the gear stack to turn it just a bit to line up the splines with the suba spool. Once it was lined I pressed it the rest of the way on. The rest of the build went fine.

This time around I brought my partially assembled tranny to a local transmission shop to get the back lash set and look over the tranny. I just didn't have the confidence last time and I thought I was destroying my gears every time I was driving the van. It cost me $200cnd to get the work done. It was money well spent and I dropped it off before work and picked it up on the way home. The owner explained what he did and answered all my questions about how to do it myself next time. He opened up the back lash a bit which he does when setting up diffs for race applications (which is good given that I drive hard, I'm running an SVX motor and the van is heavy). Opening it up puts the mesh out towards the stronger part of the teeth. He said the lash will move a bit toward centre after its been ran for a bit? i dunno? he is the pro. He also said the only draw back with the backlash opened up is tranny temps will be a bit higher, but race cars usually also run tranny coolers. He said temps around 80C is normal. I've put a 300 hundred kms on it and had runs up to 140km/h, my temps are 65C on the stack end and 75C on the diff end(+/- a few degrees) seems good to me.

Another thing that was different is I now got oil coming up out of the dipstick. I never had that issue before. Nothing changed other then the ring an pinion? I dunno why it happened but the remedy is to cap off the dipstick tube. I do have the subarugears supplied vent which is in the old recommended location. It's now recommended to be put on the side. Check on the casing page of the subarugears website for where to locate the plug.

Aside from a few changes the new gears are now in, the van is back in action and having a 5th gear is awesome.

And as always Todd at Subaru gears answered all my questions in a timely fashion. Great customer service is great!

Regards'
Jon h.

And...... since everybody love beige! (or what ever colour you wanna call it) Bonus picture!

Mon Aug 01, 2016 6:58 pm

Thanks Jon, I appreciate you updating this with pictures and your own positive results. Have fun!

Wed Aug 03, 2016 11:18 am

My apologies on the lapse in discussion and progress on this thread. July tends to be a very difficult month for me to get anything done (project wise) as a majority of it is spent traveling. This year was an extreme case as travel spanned from June 23 on up through the end of July… 5 weeks of travel covering over 5000 miles of roads in the western US (Back and forth to Boise, Monterey, and finally on up to Port Angeles to the starting point of the Airhead Parts Treffen 18 VW cruise http://andretoselli.com/airheadparts/treffen/). Midway through, I rounded back home to secure the Ring & Pinion package as I did not feel safe with it sitting on my door step the entire time.

Now that the trip is over and I've had a few days to re-acclimate I plan to dive back into the gearbox this weekend. I'm looking forward to mesh results and driving experience similar to Jon h. (Hammy1)! Thanks everyone!

Also, nice clean Westy you've got there Jon… Is this the one with the SVX/5mt combo hiding out back?

Mon Aug 29, 2016 5:30 pm

Alrightey all, I've been able to find some time to delve back into my Subaru 5MT Vanagon project and have since re-setup my gearbox with the new, version 2, 2wd Hi-Performance Subarugears Ring & Pinion kit.

When comparing to the agony I was faced with on the originally supplied kit design, this version 2 kit is dead-nuts on!! The freshly supplied Pinion Depth gauge fit perfectly in the case half, and the measure indicated on the depth gauge slider was dead-on once I had mic'd my pinion shims to find the corresponding combo. The setup up through this step was smooth sailing.

Unfortunately, I had gotten a bit ahead of myself with the pinion gear assembly and had already press-fit the pinion shaft into the pinion gearstack and set the Subaspool, pinion washers and pinion nut in place, torqued to 88 ft/lbs and peened. This is when I remembered that the backlash tool needed to be in place where the pinion washers were currently. As I don't have a bench vise available at my build site and I didn't want to waste additional time pulling the pinion nut off again (which takes a bit of fancy vise-work with the configuration I am using), I opted to move forward with the build to get some initial mesh pattern reads using the "backlash-by-feel" approach that I had done previously.

With the pinion depth reading perfect, I continued through the physical backlash setting procedure until the mesh got to a point that felt right. At this step, it was time to take the gearbox apart and mark the virgin gears with gearmarking compound. With all changes static, I reassembled the gearbox and spun the gears forward and backward using both the exposed Subaspool end of the pinion shaft as well as the output shafts of the differential (to obtain greater load on the geartooth faces).

Upon disassembly, I was shocked to see how close the setup was to the ideal pattern. Taking what I've learned from the Pinion Depth / Backlash YouTube video posted at the start of this thread I felt really good about where the pinion depth fell in as the wear marks are very near to the center of both the drive/coast sides of the gear tooth. That said, the symmetry suggested that things were good with respect to pinion depth, though the video suggestion (as well as what I've read in the Subaru transaxle setup document) indicates that these wear patterns should be slightly biased toward the toe of the geartooth as opposed to the center to account for the anticipated pattern stretch under load. Regardless, I knew that I was in the ballpark as my patterns were very near to the patterns as reported in the preliminary setup from Todd (Subarugears) previously in this thread.

In effort to pull the pattern in towards the toe of the geartooth, I would have to move the ring gear & differential deeper into the mesh of the pinion gear. So, instead of starting from scratch, I opted to simply turn the differential bearing cups 1/2 tooth from their current setting, first by releasing tension 1/2 tooth on the bearing cup opposite the ring gear, then by increasing tension 1/2 tooth on the bearing cup adjacent to the ring gear. Collectively, this would have the impact of reducing the backlash by 0.001 inches. This approach appears to have been ever so slightly effective, though I still do not have the drive mesh pattern near enough to the 1/3 mark closest to the toe of the gear tooth. As a result, i decided to move the backlash in another 1/2 tooth to have obtained a combined adjustment of 0.002 inches. As the target backlash range is 0.0051-0.0071 inches, moving the backlash in an additional 0.002 inches should be permissible assuming I got lucky and my initial pattern was at the high-end 0.0071 inch mark.

The chart below represents this progress:

Personally, I feel that the +0.002" graphics look the best for both the drive & coast side, I would like to hear any feedback for, against, or indifferent regarding the patterns as read. I realize that the markings are very similar as we are talking in terms of the visual impact of 1/1000" ring gear depth engagement. What I'm noticing in the readings are the drive side smudge profile is moving closer toward the toe of the tooth as well as centering better between the top land and the root so that none of the smudged contact points are extending over into the top land (as appears to be the case at the +0.0000" graphic). With respect to the coast side, there doesn't appear to be very much lateral movement toward the toe or heel, though I do notice the similar focusing of the smudge area toward the middle of the tooth between the top land and the root.

Ever seeking perfection in this endeavor, part of me feels that taking the ring gear in an additional 1/2 tooth cycle or two might land me at a perceived perfect… though at this point I also feel suspect as I've already taken the whole ring and differential assembly in a whole tooth from what felt good to begin with. Based on some of the patterns I've seen on this thread from Jon H. (Hammy1) and Todd (Subarugears), theres a good chance that I've already dawned on the ideal and should proceed with the assembly process. At any rate, I'm looking forward to hearing what the forum thinks. Thanks to all of those who have chimed in with support and encouragement. Cheers!

Mon Aug 29, 2016 6:07 pm

Great to see this has come together so well now. Phew!!
I would be happy with any of those to be honest and agree that the 0.002" adjustment looks just that smidge nicer.

Having said that - please confirm what your backlash reads now. You can put the dial gauge on the flat 5th gear nut at worst or seeing as you're seeking perfection, don't get lazy at this point - unpeen the pinion nut, fit the measurement tool and see what it all reads.

You don't want to set the mesh tighter than the minimum spec or it will wear prematurely.