Syncro transaxle noise - bad mainshaft bearing

[tim_ha]

Hi,

I am seeking advice from those knowledgeable in manual transaxles.

I have recently noticed a new noise coming from the transaxle. In neutral, when I let the clutch out, there is an obvious grrrrrrr sound coming from the transaxle similar to the noise documented by Syncro Jael in this thread: https://www.thesamba.com/vw/forum/viewtopic.php?p=8235220. I first noticed the sound just after a shift linkage rebuild and install of the 025 Motorsport shifter. I think that the noise is correlated with the shifter work I did, but am not totally sure. I did have the transaxle rebuilt about 30k miles ago, and run a 2.2 subaru so I would hope the rebuild would last longer than this but the van does have larger tires on and sees a decent amount of 4th gear highway miles with no oil cooler.

I am now reaching out the the amazing collective knowledge on this forum to ask some questions and get some advice.

Is it possible that the noise is the result of me not being careful enough while doing the shift linkage rebuild? My thinking is that when I used a hammer to separate, and later couple, the front and rear shift linkage, there was some force transmitted through the linkage into the transaxle. Could that force on the 3/4 slider have pushed the 4th gear idler toward the mainshaft bearing causing it to rub and make the noise? Or, could 3rd gear have been pushed toward second causing those two to rub together in neutral? As I understand it 2nd spins with the main shaft while 3rd does not.

The bigger question is how should I proceed? I am a mostly competent hobyist mechanic but I don't have any special transmission tools. Is it worth it or even possible to drain the transaxle and scope it to try to see what is going on? I have spoken with Mr Gas and can certainly bring my transaxle to an expert, but it would be nice to avoid a total rebuild if it is not necessary. Are there any other experiments to perform that might help me figure this out?

Thanks in advanced to any help or advice you have for me!
~Tim
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

[dougnlina]

Sounds to me that if you are really hearing the noise you think you hear that you should probably at least prepare for the possibility you will need to pull the tranny. Dont discount that the noise could have been there before wacking on the shift linkage and you just did not notice it. If you are SURE that it was not there before the linkage change, is the linkage adjusted correctly now? What happens if you completely disconnect the linkage at the transmission, does the noise go away? Noises are the van telling you somethings up and if something is going south it is usually more cost effective to address is sooner than later. You could certainly drive it to someone with a greater ear for syncro transaxle noises and get a "second opinion". I would not take any long trips until I have it worked out though.
Good Luck...
_________________
"Grover" a '87 Syncro Poptop 1.8T
"Olive" a '60 Ragtop Beetle (retired)

[Howesight]

Right after I had my Syncro transaxle rebuilt by Darryl Christiansen at AA Transaxle, it made a similar noise when the engine and transaxle were hot, the engine was idling, with the clutch out, in neutral. It is about 30,000 miles later now, and still the same. This rig has a 230 HP SVX engine.

I run Swepco 210 gear oil that is like molasses when cold. When hot, it thins out considerably. My transaxle had Weddle higher 3rd and 4th gears added along with the South African oiling plates and new bearings throughout at the time of rebuild. I drive this rig with care with respect to shock loading. With respect to highway driving however, it has (especially when Mrs. Howesight has been at the wheel) been driven for hours at 80mph.

These days, knowing better, we stick to 70mph and under on the highway. All still seems good, but the transaxle sound at hot idle is still the same.
_________________
'86 Syncro Westy SVX

[MarkWard]

From memory, The 3/4 slider is on the mainshaft and the 1/2 slider is on the pinion shaft. 4th gear idler is on needle bearings. It’s forced against the mainshaft inner race every time you select 4th.

I’m leaning towards coincidence. The hammer energy from separating the shift shaft coupling likely didn’t cause permanent damage. The suggestion of disconnecting the arm from the transmission and retesting.

I’m not familiar with the shifter assembly you installed, but if it’s a solid assembly to firm shifting, it could also transmit sound from the trans up to the cabin.

[Phishman068]

New noises from new/different shift linkages is a real phenomenon seen in lots of cars (and documented in the vanagon community). Plenty of folks have switched to Urethane mounts or a big shot shifter and complained of increased transmission noise, a surprising amount of which is carried through the shifter.

It's very possible that your new, stiffer shifter is just transmitting a noise you weren't used to hearing.
_________________
http://www.thesamba.com/vw/forum/viewtopic.php?t=559766&highlight=winter+rust
http://www.thesamba.com/vw/forum/viewtopic.php?t=482402&highlight=sunroof+syncro
http://www.thesamba.com/vw/forum/viewtopic.php?t=569774
http://www.thesamba.com/vw/forum/viewtopic.php?p=6864936#6864936

"Along with the ability to go fast, one looses the desire to hurry."

[Sodo]

^^Agreed ^^the shifter mechanism change can amplify or transmit “new frequencies” that were previously unnoticed.

In neutral, a loose mainshaft bearing will make noise. It made less noise last time you drove. It will make more noise the next time. The noise goes from imperceptible to “noisy”, passing by the threshold of perception.
If this is happening, your gearbox magnet is going from “bare” to inundated with mainshaft bearing hard surfaces (concurrently) but you’d have to be “looking” periodically. With have a known baseline for comparison (‘cuz your magnet was clear at x,xxx miles ago).

The low-gear housing cluster (your 6:1 granny & reverse) _can_ have a benign gear buzz if there are older gears in there (likely). It takes a practiced ear to tell the difference between gear lash buzz (OK) and bearing slop (not OK) because the sounds are happening at the same time & conditions.

If it makes the noise even when cold, I’d guess it’s a mainshaft bearing failure. But theres so many variations. Some people like thin oil for the easier shifting. Thin oil makes different sounds than thick oil. And we’re discussing sounds by typing….. lots of variables.

This is an example where you wish you had clean gear oil “recently”, and thus the option to check a recently bare magnet for “increasing” stuff. I understand this takes fanaticism but, then such details as: Syncro, 35years old, rare, valuable, NLA parts, big bucks, massive HP increases, specialists required. Etc etc. etc. can inspire bouts of increased maintenance (=fanaticism).

WRT Hammering on a linkage while in 3rd/4th could shake loose some nested broken parts on a broken 4th hear hub. This is _un-likely on a 30k rebuild_. But you didn’t say who rebuilt it. There are some who would (still) send oit out with an unknown “old” OEM hub not yet broken, with a good 10k of remaining life.

And we don’t know how hard you hammered. Its not a good thing to do. Neutral is a “position of a “coupler”. In a proper gearbox you can’t move the gear cluster around with the coupler. If your mainshaft bearing is loose in its bore then yes hammering on 4th gear could shove the mainshaft cluster forward where 4th gear now rubs on the case. But the van has to be moving to rub 4th on the case, and your noise conditions is “van stopped”, so this is not the noise.

This is why monitoring gearbox temp is useful (for bigger engines), cuz at 180F the mainshaft bore is getting wallowed out on a new trans. 170F on an older trans etc, , and on an old old beatup trans, it can be loose at room temp.

Pray it’s just granny gear lash. If you’re running a (thin?) synthetic, I’d put regular 80w90 in it so you can at least compare sounds. You will see the magnet & clear it at that time. Then pay attention to the sound - look at the magnet again in 2,000 miles.

FYI ….. on a Syncro, with rear wheels 22 inches higher than the front (floor at angle 13+ degrees) , you can take out the drain magnet (for a peek).

If your current oil is dear ($$) to you, and “recent” note it will self-purify over a few months (in a water-clear jug) and you can put it back in…..if you’re happy with magnet cleanliness and noises etc.

I’m typing on a phone out in the woods, and probably should quit for now but there’s lots of detail to this subject of Syncro gearbox noises. I have a 40k gearbox that did this and we found ‘electrical erosion’. Syncro Jael found a cracked mainshaft bearing race. I really feel for you, especially in the opening months of Van Season. I know you’re praying its just “granny gear lash at idle”, which won’t make magnet fuzz. Hope this helps and doesn’t just confuse.

[tim_ha]

Thanks for all of the replies so far!
@sodo, That is an impressive amount of typing on your phone. Thanks for the thorough reply.

From the feedback I have so far, I will be disconnecting the shift linkage at the transaxle to see what things sound like in that state. As part of the linkage rebuild, I found that the roll pin that holds the cup onto the rear shift linkage was very worn and the hole in the rear linkage bar was ovalized, so I ended up drilling it out and replacing the roll pin with a bolt. This would certainly explain much more noise being transmitted through the shift linkage.

I am currently running Swepco 210, but want to change to 202 and am probably overdue on an oil change anyway. I will pick up some 80w90 and monitor the magnet. Thanks, sodo, for the tip on being able to check the magnet with the rear end high.

The previous rebuild was done by a reputable rebuilder in Colorado. My ring and pinion were bad, so I had a new (weddle?) r/p installed along with a slightly taller 4th gear. IIRC, 3rd may have been replaced with a used gear that he had sitting around. I also had the 4th gear oiling plate installed.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

[Sodo]

(Ooops double post)
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[Sodo]

Re: The roll-pin to bolt change.
Either should be “tight”.
There is no difference between a tight roll pin and a tight bolt.

I have a “Smallcar” Subaru conversion.
It had no “engine ground”; built per Smallcar’s specs (back in the day).

And we found well-defined electrical erosion damage to the mainshaft bearing.
It was so specific this bearing failure example pic could be used in a textbook.

This is caused by a years-degraded groundpath across the transaxle assembly, the current finding its own way but exiting at the “well-maintained OEM forward transaxle ground “ (= Satan).

In a “normal gearbox trashing” this electrical erosion would not be seen because the gearbox would be driven noisy for many thousands of miles; thus the electricalpattern would become obliterated, the evidence all piling up on the drain magnet.

Over the years we’ve see blame placed upon: poor bearing quality, high horsepower, destructive driving style, oil brands, contaminated lubricant, improper assembly, there are many ways to reduce bearing life. And obviously, the more of the above conditions…..the worse.

But by “some strange providence” (friends in high places ), this one 40k mile gearbox was disassembled while the electrical assault was still evident. And we THINK, those other assaults above were not committed****. It had definitely suffered “no engine ground” and “400w headlights” and “2nd battery) for its first 20,000 miles. I added a starter ground, deleted front ground, then drove 20,000 more miles, stopping when the noise level rose to become audible.

****edit & clarification: There were several 75-85mph jaunts for hours & hours (hundredss of miles). I saw lots of metal in the filters, and assumed that 75-85 was just too high duty-cycle for a VW gearbox, even cooled/filtered. So I stopped driving like that. Then …. Upon disassembly, discovering that the bearing was damaged by electricity…. Well of course a damaged bearing is going to shed steel under such duty.

Point being (to Tim) …. premature mainshaft bearing failure can be caused by alternator current choosing a path thru your gearbox bearings, as its trying to get to the forward transaxle ground. A dutifully maintained fwd ground …. making it worse. Now, does that SUCK or what? Especially bad if you have big headlights or a hungry LiFePO battery. Everyone should delete that fwd OEM ground and not risk your gearbox. But you must add the proper chassis ground from the starter bolt.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[Sodo]

Sorry for too much of my gearbox in your thread.
If you get it apart, (If the noise is a low-miles mainshaft bearing….). I’d love to see closeup pics.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[tim_ha]

I was able to accomplish two things on Monday. I changed the swepco 210 that had about 20k miles in it and replaced with Valvoline 80w90. I was happy to find no big chunks stuck to the magnet. It did have a pretty good tree growing off of it but it was all tiny bits that sort of just smear into a gray paste when removed.

I also disconnected the shift linkage and crawled under with the van idling in neutral to have a listen. I don't hear much of a difference in noise from inside the cab with the new oil and disconnected linkage (darn!). I was trying to isolate where in the transaxle the noise is coming from, but that is pretty difficult. It does sound like more of a buzz when up close to the gear box. Could be a bit louder at the front end where the low gear/reverse housing is but too hard to tell.

The wife and I are trying to decide if I should just pull it out now and send it off to be rebuilt. It might be a good time, but we need to figure out another car as the van is a daily driver used to ferry our kiddo around town.

If/when I get it rebuild I will certainly ask Greg (Mr. GAS) to send some pictures of what he finds and update this thread. One other consideration is that Greg said that the Rancho Transaxle billet gear carrier housing is maybe 2 months out and I would consider upgrading mine at this point if doing a rebuild anyway.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

[Sodo]

If you can tell the difference between (gear teeth) buzz and a bearing growl, it could just be the low gears buzzing. Which could be OK. I suspect that takes some time&experience to discern. Which you are gaining, right?

I'm running Valvoline 80W90 and I don't hear any gear buzz at all when cold. My trans is 'new', less than 3,000 miles. I'll listen again hot.

No metal is good metal BTW.
There's a bunch that comes when the trans is 'new' that gets rolled flat after going thru the gears and bearings tens of thousands of times. That's why it feels like paste, it's like slippery leaves on a wet sidewalk.
Theres a long mid-life stretch in a gearbox lifetime where the magnet should be coming out 'clean'.
Then it starts 'making metal' again when it's giving up the ghost in the end.

Of course you don't want that at 30,000 miles....

A good way to look at magnet dust is to carefully wash the heavy oil away with a aerosol spray cleaner. You're pressing the spray nozzle _very lightly_ to wash the 90w out. It's very gently, almost just dripping, allowing the magnet to hold onto the steel as the heavy oil is thinned.

I'd take a quick (13 degree) peek soon, like 100 miles into the new Valvoline, mainly to start with the magnet clean of leftover metal from the prev 20k mile cycle. Use duct tape to pull off the last of the chips.

If it seems good, it would be hard to take the gearbox out at the beginning of van season.
I'd take another peek at 3,000 miles (?) and make your decision from there.
While paying attention to the noise level.
Of course _increasing noise_ is a bad sign and you should stop using the gearbox as soon as you determine ANYTHING is wrong inside.

"They say" the stringy particles on the magnet are bearings. I did not have stringy particles on mine, they were little flat flakes. Not really 'slippery' flat flakes though.

And the noise will be increasing too. The particles will roll out into "flat" paste over time. It's nice that they become benign, but the process to do so, fatigues the surfaces and causes loss of gearbox lifetime. Much better to dump trash out rather than use your gears/bearings to make them benign.

Note that GTA has the Pioneer WagenWerks billet gear carriers in stock now.
I did not know that Rancho was doing one too.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[tim_ha]

I just got off of the phone with Mr GAS. He has had my transmission for a few weeks and started to reassemble today. He did indeed find a bad mainshaft bearing! I have updated the topic title to reflect this diagnosis. He also said that most of the other parts in the transmission that he has looked at are in great condition.

So, the good news is that I didn't rip out the transmission in peak camping season for nothing.

The bad news is WTF, why after ~30k miles over 5 years did that bearing fail and how can I prevent it in the future? Greg mentioned that the failed bearing is a German bearing which have been NLA for a while. Now, all the mainshaft bearings come from Pakistan. I guess that I will be adding a ground strap to the starter and doing more frequent gear oil changes moving forward.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

[Sodo]

Can you get that bearing and take it apart?
Or send it to me?

Did your van have a SmallCar conversion?
In the past Smallcar had no engine ground, using ONLY the forward transaxle ground.
Sending all of the alternator power thru the gearbox.

Tim Ha I think you may understand the problem.

I hope Smallcar has changed their grounding.
Grounding is best done "early".
Ground starter case, ground alternator case.

Starter is the bigger spark of the two but it ain't got nothin' on the alternator for steady erosion.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[tim_ha]

I'll ask Greg to send the bearing with the transaxle and post up some pictures.

Nope, I am running RMW conversion and DO have an engine block ground strap. I'll be sure to double check the alternator grounding too. Thanks for the anecdotal experience with a mainshaft bearing failure.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

[MarkWard]

In my experience current will seek the path of least resistance. For the life of me I can’t see how the easiest path is through the engine case to the bellhousing, through a needle bearing into the mainshaft, down the mainshaft into the large main bearing inner race, into the balls, to the outer race into the bearing carrier and to the nose cone bolt to the ground strap. VS flowing through the case proper.

Don’t see a problem adding a ground to the starter base and don’t doubt that current passing through any bearing is not good. Just seems like a stretch that this happens often in a vanagon transaxle.

[Sodo]

Prob not much when the van was new.
Bolts were shiny. Now they have the white dust of
steel.vs. magnesium.for.years
(if you take one out and look).

As those multiple series interfaces get old, and corroded, then yes electricity will choose the shiny shafts in its mad rush to the far end of your gearbox.

====================

The resistance of each interface is additive.
As the resistance rises - theres more potential to seek other routes.
Dissimilar materials, outdoors, the electricity wants better.

Down the mainshaft or Pinion shaft is "a LEG of least resistance" so the electrons go "there" looking for any way to get to the nose cone ground.

So the Q is, how does it get across the bearings?
--->At the asperities, where there is microsopic metal-to-metal contact.
Mechanical wear is happening here, the less the better, right?
The wear gets worse if it has to pass electricity too.
It erodes. Steel departs the bearing (or gear) never to return.
Oil blackens. Black magnetic dust in the oil.

More electricity shunting thru the internals = more wear.

Tiny chunks of metal in the oil makes a bridge from bearing race to ball to race.
And there can be thousands of them bridging all the time. Dump out sparkly oil.

The erosion is cumulative.
It doesn't degrade your eqpt immediately, it takes time.
Like one dusty road doesn't ruin your rings but continual dust is a continuous assault.

Non-sensical grounding at the far end of the gearbox "enables this problem".
Whereas proper electrical grounding would simply....."delete the problem".
Now you're down to "only mechanical erosion'.
It will be less erosion than "mechanical + electrical".

Another guy told me "ground early, ground often".

========

I think the mainshaft bearing 'gets it' because of it its high&dry contact with 4th gear.
Constant thrust of the helical gear seals the contact area and it dries of oil.
Lubrication is key, oil separates the steel parts, but there's not much lube in that area.
Lubrication at 4th gear is not easy to change (but there is a driving style you can perhaps adopt.... 👍🏽👍🏽Periodic decel! 👍🏽👍🏽 opens the gap and lets oil get in).
_So much_ of the vehicle's life is spent in 4th gear.

I was thrilled to find that the 130Amp Tribeca alternator fits all Subaru EJs.
And added a big hungry house battery, (150 Ah LiFePO4)
And 400watts of headlights, (e-code Baby!!)
long night-driving..... There were some times that were hell on my mainshaft bearing.

But the electrical erosion component goes away when there's no place for the electrons to go.
So move the ground to the starter, add a chassis ground to the alternator.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb