Transmision Suggestions.

[SyncroTrev]

Hey everyone. I am halfway done dropping the transmission out of my van. I have had two Syncros over the years. Both with engine swaps and re-geared transmissions. (3.3 SVX and 1.9 TDI)

I will be going to German Transaxle as I live in Bend OR, I think the proximity will be nice. I know what I like for gearing already. But looking for other build suggestions and opinions from people.

In general from what I have read I want to go with the newer "straight cut" GT gears vs. the Wedel's that I have ran in the last two vans. I also want the newer GT fluted main shaft. (I believe thats what it's called.) I am sure German Transaxle will have lots of suggestions too. But want to get feed back from real experience.

Has anyone been running the GT set up for a while now that can tell me what they think?

I drive my vans nice now days. My biggest wants are the following:

1) The best lubrication possible. I don't necessarily need a filter system as I don't mind changing the fluid often.

2) I pull long days in-between camp spots. So the van is in 4th for long stents. One of my main concerns / wants is driving the temps down in this situation. I can tell it gets hot fully loaded in 4th for long pulls. I'm not super into an external cooler unless that is the only way and what everyone recommends.

3) Obviously longevity is important.

4) is there anyone re-gearing the granny gear lower? I know that sounds crazy, but I am running 30" tires and low has lost its magic crawl ability. I just need a little more there with the tire size I am running. Especially for the trails in Moab!

Lastly I know there are a few dudes out there making really cool shit. Like Matt at Pioneer Wagen works and others. I don't have social media, so I miss all the cool new stuff. So please school me on anything new and improved coming out.

Appreciate all your time and suggestions.
_________________
1989 Vanagon Syncro
Adventurewagen Hightop
Westy Cab Interior
1.9 TDI ALH
Bend, OR

[dobryan]

To keep the temps below 160f on the highway at high speeds with non-stock engines the only way I know to do that is with an external cooler. It is what I do.

If you are only toddling around at 55mph in 4th you'll likely be fine.
_________________
Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[Sodo]

You have already stated that you found ratios for 30" wheels that you like, so I won't comment on that.
Your wheels are almost 17% bigger than 205/70R14,
and 10% bigger than my 215/75R15 so I'd have to extrapolate a bit.

But "the details" will help with advice.
What engine, what 4th gear, and what R&P have you arrived upon? (maybe "what 3rd?)

If you like tall gearing, you have to downshift more often.

It may help to know that on long trips it helps 4th gear to downshift to 3rd.
3rd does not appear to have the lubrication deficiency that 4th gear has.
This is great for your gearbox if your driving style and satisfaction can accommodate periodic downshifts to 3rd.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop, EJ25, cooled filtered (original) gearbox
....KTMs, GasGas, SPOT mtb

All Vanagons should do this:
Add direct starter-to-chassis cable THEN delete ground strap at front transaxle mount.
The best time to do this mod was in 2010. The second best time is TODAY.
If your starter is slow, this is MORE important.

[SyncroTrev]

Sadly, I have not rebuilt this one yet, so I am limited on what I know about it. I do not have the R&P info.

But 3rd is 1.14 and 4th is.70

I like it all how it is. So plan to do a direct swap of parts we find inside. But with the GT equivalent.

[Sodo]

[SyncroTrev]

[Sodo]

SynroTrev if you those who HAVE transmission mods to chime in,
you might edit your post title to
"Syncro trans mods? big diesel, big tires, long days"
I almost skipped over it thinking "hmmmmm another auto-trans question".

====== edit=======
OK your "travel mph" is 70mph for long distance.
65mph seems to be "the cusp" for my van for stabile temperature.
Lifted Syncro, EJ25, .85 stock 4th and 4.86 R&P with a rocketbox ontop.
Where under 65 it sorta maintains under 145F , but over 65 the temperature begins to climb. This is WITH my pump a'pumpin'.

I don't know how high it would get, I've never allowed it beyond 165°F.

I don't know what temp is "the cusp" for a non-pumped trans.
I can try it with the pump OFF, but don't have that data currently.
I try to get it in the summertime, then forget and then it's winter.

Speed, external festoonery, ambient temp, grade, headwinds, gearing
Lots of inputs.

the WBX pulls down on a grade or headwind and downshifts to 3rd gear
while the torque beast remains in 4th for hours.
So many different conditions.
I'm going to guess that your gearox temp get kinda high (and higher in the summertime).
====== /edit =======

OK a pumped up TDi, that's a tall order. GTA is not gonna offer a warranty (if they ever have....)
I have no doubt that it drives just wonderful though.
Man......if there was a trans for that engine, it would be a dream vehicle.

The Vanagon 4th gear has lubrication problems even with a WBX, if driven on long trips sustained 4th gear.
Cruise control is a "usual suspect" for sustained 4th gear thrust.

The Vanagon gearbox a poor candidate for "big conversion engines" but its all we have.
It gets worse

part due to the higher forces on little gears,
and
part due to "less downshifting" that a big engine "enables".

GT's drilled mainshaft is to lubricate 4th gear continually (and 3rd gear, and the rear needle bearing).
To use GT's drilled mainshaft you must have a pump, and it's an involved installation to plumb it.
The drilled mainshaft lubricates 4th gear directly. I have NOT heard of GTA plumbing a mainshaft.
You can ask GTA and please LMK if GTA has ever done this specialty mod and what they say about it.
You have to cut/weld clearance on your Syncro frame crossmember to do this.

You wrote you don't want a pump and I can understand that.
The next best thing going (passive lubrication) is the GT straight-cut gears, which don't "block off" the lubrication entirely - while under 'thrust'.
Straight cut gears leave a tiny (up to 1/2mm) opening that oil "may enter" but its still against the 3,000 RPM 'outflow'.
The outflow (due to 3000 rpm) opposes oil entry.
But at least entry is "possible" with the storm of oil inside a gearbox.
With straight-cut gears you get "noise" but thrust doesn't close the oil entry gap.

This video explains the Vanagon 4th gear lubrication problem.
https://youtu.be/jgO6WPfLuOw?si=uprnS2MB7KdQ0YbF

Straight-cut noise may be more than a people-annoyance.
Noise is an assault on gears and bearings; but nobody knows if the noise causes loss of lifetime.
There's no OEM testing/disassembling/observing any of these mods.
There is at least hope that the lubrication solution (assumption) offers more improvement than the noise detriment (assumption).
Mike at Rancho has a rather succinct opinion: "a quiet tranny is a happy tranny".

I will add: "a quiet 150°F Vanagon tranny is a happy(er) tranny."

I think you should add a transmission temperature gauge.
Choose a digital gauge that's accurate in the range of 150-180°F.
Don't get a "trans gauge" that goes to 350F on a gearbox where 180°F is the beginning of damage.
And you need accuracy at half of that range to drive by the gauge.

You need to know

"it's at 165°F now,
is what I'm doing now,
cooling to 164°F yet?
-or-
do I have to slow down?"

There's a lag time too.

Don't get "analog/needle" style to accommodate your peripheral vision.
(as you hurtle around S-turns while watching your competitor's every move in 3 mirrors.)
Need digital readout, and accuracy.

==== Your Qs ======

1) The best lubrication possible. I don't necessarily need a filter system as I don't mind changing the fluid often.

I'd use Swepco 201 for that beast, maybe even 210. Get two batches going, and settle the metal out of it, then switch it for the other (purified) batch. pretty easy once you get into it. I'm not sold on Synthetic for the low max temps these gearboxes require. Synthetic shines after 230°F, onwards into the 300s, which way past our 180°F limit.
I am no oil expert whatsoever.
But the Swepco engineer recommended 201 or 210 when I told him about our temperature limitations. He said 210 for max protection but there will be harder shifting when cold.

2) I pull long days in-between camp spots. So the van is in 4th for long stents. One of my main concerns / wants is driving the temps down in this situation. I can tell it gets hot fully loaded in 4th for long pulls. I'm not super into an external cooler unless that is the only way and what everyone recommends.

A temp gauge will tell you if you need a cooler for your driving style. There's also downshifting to cool 4th. Perhaps some relief by foot-off-gas decel.

If you drive 70-75 it will get hot. 60-65 seems is better. These recommendtions are based on 'sparse' anectdotal data. And the conditions are not controlled. No data whether its a slippery ( ) tintop or a lifted Hi-top Syncro with 2 kayaks. Winter is vastly different than summer.

3) Obviously longevity is important.

We don't know yet (the contributions of the modifications). Look at a torque curve for a WBX. Transfer that max torque number to the torque curve of your existing engine and try to drive that torque "most" of "your accumulating odometer miles".
This is for longevity.
"Retirees" may have the extra time to drive for longevity.

We don't know the quality of the aftermarket parts. They are not vetted as approved OEM suppliers to VW. And especially when a bunch of your 250,000 mile gears are re-used in your build.

There's no way to compare or pre-suppose any longevity "wishes" while at the same time, everyone is doubling the HP and adding more weight and external festoonery on the top and sides of their vans.
This is a very big wish.
Wishes/Horses/Beggars/Ride applies.

4) is there anyone re-gearing the granny gear lower? I know that sounds crazy, but I am running 30" tires and low has lost its magic crawl ability. I just need a little more there with the tire size I am running. Especially for the trails in Moab!

GT has talked about offering a 7:1 granny set, but the 6:1 is so far beyond the strength the Vanagon trans, increasing the output torque is almost silly. Especially with a pumped diesel. I do agree it would be nice to slow the granny a little more, but along with that you would need a throttle limiter to prevent that engine from every getting up on its torque curve. You should worry as it is (in granny). There were folks back in WBX days who would advise to limit RPM in granny to 2500 to make sure you don't over-stress the R&P (or cases, shafts, bearings etc). The trans was not designed for that granny.
The Syncro Granny is a 'strap-on' to the 2wd Vanagon gearbox that (perhaps?) became viable when they added PTOs for the Finnish tax code.

Lastly I know there are a few dudes out there making really cool shit. Like Matt at Pioneer Wagen works and others. I don't have social media, so I miss all the cool new stuff. So please school me on anything new and improved coming out.

Pioneer made an incredible CNC low gear housing. It's got to be 5x as strong as the cast low-gear housing. It has an oil port to feed the GT drilled mainshaft and a front drain magnet to alert you, or catch trouble up-front. And a CNC gear carrier housing too.

Pioneer threatens to make a stronger main case too. Case strength keeps gears at proper mesh under high torque.
But all the gears are all still too small for the big torque we like.
The Vanagon R&P is 7.4" however, is fairly healthy. Ever heard of a 9" Ford?

But the Syncro fellers still break R&Ps, I think because of the granny torque. But many continue driving with loose, noisy bearings, which stresses, chips tooth-tips.
I know most don't change the oil on often enough, or ever, if following the VW owners manual.

-----> Does anyone happen to know the diameter of a Subaru 5MT R&P?

For gear carriers though,
the NEW GT CNC gear carrier gets the nod, with its new "steel sleeved mainshaft bore". The 180°F limitation (may) go away if this works out. I have not heard of any testing conducted.

=========My stuff ======

My preference is the GT oiled mainshaft, and oil temperature cooled, filtered, AND still settling/purifying the oil.
I have all GT gears and 4th gear is a small-tooth helical cut, (like VW)
My tranny is quiet as a mouse, but only 26,000 miles currently.
The cost was more than $12,000. I don't know the real end-cost because there was some bruddah-bruddah and I had collected parts along the way.
Paul guard is a friend. We chat about stuff and he helped me out with stuff.
I will agree adding all that cooler/filter mumbojumbo and keeping ontop of it is a BIG effort.
Cooler/filter only recommended for the enthusiast who's gonna keep ontop of it.
The type who says "I'll be buried in my Syncro".

I drive 65mph for MOST of my highway miles, mainly to keep the EJ25 off it's peak torque output.
I'm pretty sure I don't have to downshift for oiling 4th, with oil being pumped into 4th gear continuously.

If I need to go fast..... I go fast.
But the bulk of the miles are 65mph

My pumping system starts when the gearbox reaches 100°F thus it starts up soon after I get on the highway.
It usually runs at 135-140°F.
If it hits 150° the fan comes on and it never exceeds 151°.

===========

OK that's the landscape when you over-drive a small gearbox with a big engine in a 40 year old collector car.

Hours and hours, long days, lots of cars going by.
How many 40 years old do you see in a long day?
Few.

OK that's a lot.
Let me close with this.

A Swepco engineer told me "don't kid yourself - you can solve part of the problem with chemical means but once the contact pressure exceeds what the oil film can keep separate, there will be more wear-metal in the oil and you gotta get that out if you want it to live."
The Swepco engineer is who suggested gravity-settling the oil which results in 100% purity.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop, EJ25, cooled filtered (original) gearbox
....KTMs, GasGas, SPOT mtb

All Vanagons should do this:
Add direct starter-to-chassis cable THEN delete ground strap at front transaxle mount.
The best time to do this mod was in 2010. The second best time is TODAY.
If your starter is slow, this is MORE important.

[MarkWard]

I’m running the square cut 4th with a TDI and a 4.14 ring and pinion. From memory ratio closer to stock. I was running a .77 but was too tall with my setup. You wouldn’t have that option with a syncro.

I have mixed feelings about the square cut gear. If it ends up working as designed it’s totally worth it. I’m not going to sugar coat the sound. At slower speeds upshifting you definitely hear 4th gear on or off load. It’s enough that my wife who is mechanical through osmosis can notice it.

At highway speeds the sound disappears into the background with all the other noises. But after a 12 hour day getting home our ears are ringing once we get in the house. Similar to the race car. My tinnitus is always present, but my wife notices the ringing.

As I said, if it works out as advertised, I can enjoy it. Plan is to tear down at 60k miles and have a look. The Weddle gear was always noisy and basically wore out. Weddle advised me it was expected. The GT gear set is beautiful. To nice to hide out of sight. I don’t use any cooling. I like simplicity and less points of failure. I have the 2 aftermarket oiling plates and the Weddle HD main bearing retainer. It was during Covid and I had to reuse my gear carrier, so the better 4 bolt retaining plate couldn’t be utilized.

Unlike the 2wd, granny gear is a set. If someone is making a shorter set, I don’t see why you couldn’t use it. I’d like a shorter 1st for our 2wd. With the 4.14, starting uphill from a dead stop is concerning. Stock 14s with stock profile tire.

[Pcforno]

I agree with pretty much everything said by Sodo and Mark.
I recently had my Syncro trans rebuilt by Mr. Gas. Great experience. I have an aluminum main case, GT shaft, GT gear carrier, and straight cut 4th gear. I oil, filter, and cool the mainshaft as well as the gear carrier.

My rig is heavy with 29.5 tires, and a chipped 1.8t with a larger turbo, so similar torque likely to yours, but without the punishment of the harsh diesel strokes.
I’ve only got a few thousand miles on it but so far (after the initial break in) it’s producing virtually no metal fines.

It never gets above 150 degrees, and I drive as you, 70-75 for long stretches. The SC 4th gear can be heard below around 60 mph, but disappears after that. It might be just a tad louder than the weddle 4th gear which wasn’t exactly quiet. I do have a lot of insulation in the chassis that I installed though, so YMMV.

Most of what you’ll find is educated conjecture on all these topics - you could build the best box ever with the best guy ever, but still have it fail early in some unexpected way, granted the chances would be minimized. But if you have the cash and the vanagon “sickness” then do as many of us have and build the best you can - but I wouldn’t recommend doing all that without taking full advantage of the oiling and cooling which isn’t really much more expensive once you’ve dropped a lot of money on a custom box.

[dobryan]

For Swepco I recommend 202 vs 210 or 201.

I have run all three and 201 and 210 will suck at shifting into 2nd gear (kerchunk) when the trans is cold. 202 is much better when cold. YMMV.
_________________
Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[hans j]

I have the same engine and gear ratios, however I have 215/75-15 tires. My transmission is an aluminum case and has the standard oiling plates but does have an early system for a cooler as it was done years ago. I run an Oberg filter and cooler on a manual switch and a gauge I watch on the dash. I'm running the BG Ultraguard 75/90 gear oil.

It's been great, but I usually travel around 65mph. I might have 90-100K miles on it now? I have no idea.

If and when I do it again, it will get a billet main bearing housing, rifle drilled shafts, more oiling ports, and probably some GT gears. Maybe eventually a dual mass flywheel too someday.
_________________
1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181

[Howesight]

With a TDI, there is really no way to run without a straight-cut 4th gear. The noise is not something that I can comment on as I have the Weddle 3rd and 4th gears which will likely need replacement sometime soon.

That gear choice will completely prevent the abrasion damage on the mainshaft bearing and 4th gear interface.

Given your choice to drive highway speeds at 70 to 75 mph, and given the load which the resulting wind drag places on your transaxle, you will definitely need gear oil cooling. I would recommend the gun-drilled mainshaft and drilled pinion bearing approach with all the gew gaws that go with pressure lubrication.

Driven in this way, your rig will create a lot of internal heat which needs to be controlled. But the elephant in the room with these alloy transaxles is the expansion of the magnesium and aluminum components which causes the light press-fit components to cease being press-fits and for the gears and bearings to acquire excess clearances and axial play. At a certain point, this interferes with the correct ring and pinion mesh, causing spalling and wear. All these heat-treated steel components, including the expensive GT Gears parts, need to maintain their factory clearances to avoid excessive wear and premature failure, but are ensconced in expanding aluminum and magnesium housings. Those housings need to be kept cool enough to avoid the dangerous levels of metal expansion and the best means for that heat control is pressure lubrication and an effective oil cooler.

At one time, driving home from Carmel, California, Mrs. Howesight drove for a few hours straight at 80 mph on the I-5! Not any more. We drive our rig slowly on the highway these days (65 to 68 mph by GPS) and we never use the full torque that the SVX has at peak torque rpm (4,400 rpm). Soon enough, a rebuild will be in order and we will be doing all the items mentioned above. I have gotten used to wearing my noise-cancelling headphones, so a straight-cut 4th gear will not matter to me for noise.

Many running the TDi engines have had good experiences with the dual-mass flywheel which contributes a LOT to dampening the power pulses.
_________________
'86 Syncro Westy SVX

[MarkWard]

Noise has a negative connotation. I’d call it a distinct sound. Also, either it quieted up after some wear in or I just got used to it. As I said, if it solves the wear I’ve experienced on the inner race of the large main bearing it’s a fair trade.

[Van den Broke]

The fourth gear wear issue is well explained in the video Sodo linked:


This video explains the Vanagon 4th gear lubrication problem.
https://youtu.be/jgO6WPfLuOw?si=uprnS2MB7KdQ0YbF

So the best "bang for the buck" for transmission longevity I can see is simply letting off the accelerator for a few seconds a couple times an hour when driving long distances in high gear.

Or, spend $12000 for possibly even better results.

[Sodo]

I should probably make a new video with more information.
Maybe even showing pics the lubrication damage we're trying to avoid.
Certainly showing folks more of "what to DO about it."
AFAIK it's "Vanagon ONLY". Not sure why it's not a Type2 bus problem.
But maybe it becomes a type2 problem when they have a big conversion engine.
Or maybe just that nobody's looking.

(referring to this video: https://youtu.be/jgO6WPfLuOw?si=5XUw5vrD7gJFKtZv )

[Corwyn]

Just a heads-up: I have a FAS Gen V inline four cylinder in my van and went to GTA for a transmission. I was told they would not warranty a transmission connected to a non-stick engine. Took my van and left. Let me know what happens.
_________________
'90 White Westy ("White Lightning")
FAS Gen V 2.0
The Annual Baja Rally
https://www.thesamba.com/vw/forum/viewtopic.php?t=604813&highlight=baja

"If anything's" gonna happen, it's gonna happen out there"
~ Captain Ron ~

[MarkWard]

I think you meant stock not stick. It’s hard enough to warranty unit work on stock applications. I can appreciate not offering their warranty for power added engines. There is barely enough profit doing one once. At least they are up front about it.

[dougnlina]