Howling main shaft bearings...any replacement tips?

[bastardbus]

Over the years I have come across a few buses with leaky-transmissions and low on oil end up with noisy mainshaft bearing(s).

The buses always drive-shift fine but when driving or clutch is released there is that main shaft howl. Some cases have been worse then others.

I have heard of a few folks removing the nose cone and replacing that rear main shaft bearing and fixing the problem but from what I see there is also a needle bearing in the transmission case at the front of the main shaft. Is this noise USUALLY only the larger rear ball bearing or have you found that needle bearing bad as well. Looks like one would have to do a full tear down to get to that main shaft needle bearing.

Any tips-hints-links appreciated.

T
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Samba Member #95

[vwracerdave]

Nothing last forever. Transaxles wear out and need rebuilding after a few hundred thousand miles. After you have your transaxle rebuilt with new mainshaft bearings then change the gear oil every 30,000 miles or every 5 years.
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[mark tucker]

keep them full or over full, I jack my bug up in the front and on the left side when i fill it to get as much in as possiable without moving the fill plug...witch may get done on my next trans build....after you rebuild the trans that is.

[bastardbus]

Thanks for this tips guys but I been driving buses for 25+ years plus now and I am cool with the ABCs of it all...It twasn't me ran this one low.

Story is I am pondering a trade for a very original 67 dlx bus that was probably run low on trannt oil by a PO at sometime and thus has noisy main shaft bearing howl. I am looking for info on the amount of work to replace them before I go into a deal on the bus. The bus had only 87k miles and tranny works great (I am told) It just has that main shaft bearing howl we have all seen on occasion.

I have heard-read folks often just replace the large rear MS bearing via pulling the nose cone and avoiding a full tear down. They claim this fixed their HOWL BUT there is a small needle bearing in the case as well that supports the front of the MS. To replace that one would have to do a full tear down to get to it.

Again, from what I have "heard" the issue is that rear large MS bearing under the nose cone and NOT the needle bearing inside. Wanted to see if anyone had an opinions on that as well as tips on replacement.

Might be worth the time just to replace the large rear one first and see what happens then do the full tear down if need be. A full tear down would be a good safeguard but would be a ton of work (removing redux boxes et all) and greatly affect what the bus is worth to me.

BTW you don't want to over fill a bus trans...good way to keep blowing seals.
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Samba Member #95

[Dougy Dee]

If the large MS brg is pock marked and cratered like the surface of the moon, that is your issue.
I've tore down and rebuild several hundreds of trans and have only seen about a half dozen bad small MS brgs. Those trans had been ran low in oil, buried in a swamp or out of an abused field car.

It could also be diff or RGB bearings howling...

[TinCanFab]

I just did this job for the same reason on my single cab trans. If you want a good idea of what's involved, check out my bug build thread, which is what I ended up using the center section for

http://www.thesamba.com/vw/forum/viewtopic.php?t=658092&start=160

You will need large and small snap ring pliers, press, shift fork jig and gear carrier press tool to get it apart. Also, if it's a later case, you will need the special pinion bearing socket. Ignore my other adjustment posts as you won't be changing pinion and diff shims like I did. I think a lot of people that think the average Joe can just slap in a new bearing, have never done it.
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[bastardbus]

[gears]

You need to be specific with the year transaxles you are talking about. 113 needle bearings last indefinitely, while the 002 & later bearings require replacement every time you're in the box.

Changing the mainshaft ball bearing might buy some time, but it isn't a rebuild. The pinion bearing won't be far behind (in failure).
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[Erik G]

[bastardbus]

Yup...what Erik said a 67 dlx bus trans.

`67 Tunnel swing axle...which I recall is a 113 box....?

I have seen this scenario in several buses. Either the the early style plastic detent spring plugs fall apart or axle boots start leaking badly. The trans starts running low and that rear large main shaft bearing is the highest and farther-est away from the oil supply and it is first thing to go.

Had this happen on my very first split bus, a `67 dlx I bought in `88 with only 60k orig miles. Flew to Shrevport Lousiana to drive it home to Ohio. I was just a kid with little knowledge under my belt and the PO was just a guy who drove it as a car at the time. No real maintenance had been done to the bus. I made it home but one of the axle boots leaked the entire trip. The trans was quiet as a mouse at first and started getting louder as the trip went on. We noticed the leaking boot but it was 1988 and no supply of parts on the way, no internet and no cell phone. We bought a gallon of gear oil and would top it up as we went along. Damage had been done though as once you hear the noise it is to late.

Drove that bus around for 2 years after that with no problems other then the noise but traded off as-is towards a low mileage `67 westy. Have seen a lot of other folks since then go through the same scenario and it is usually the leaking detent plugs. Not many folks even know they are there and it is a htf leak if you don't know about em. First thing I do is I replace em in every bus I get that had the plastic ones.

I have yet to try to replace just that rear MS bearing with nose cone off but looking to try it. I have a couple sets of dealership bearing pullers so should be a breeze. Anyone done this method? any tips or things to look out for?


T
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Samba Member #95

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[Bruce]

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Jim's Custom VW's can fix you up with whatever you would need for a rebuild. He's about 3 hours down 80 in Columbiana. If you can r & r the reduction boxes, and axles, that will save some money in labor.

[williamM]

I bought a "Wright" gearbox for a 12 vt bus without a core for $700 and change and core was in the < $200 range- so really didn't see any point in screwing with a noisy box.

as far as RGB s go- they are pretty straight forward repair just involving 2 big bearings and a big roller then a common axle bearing. Hardest part is getting the big plug out the back and make sure your fulcrum plates stay put when reassembling.
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[bastardbus]

Been driving split buses since `88, am a ASE certified mechanic owned a restoration shop for 15 years. I have done plenty of trans jobs and let me tell you what, it is about 1000 times easier just removing the nose cone and replacing ONE $25 bearing instead of doing a full scale tear down and-or spending $1000.

Some folks missed in this post, this is a bus-trans with only 80k some miles that was run slightly low due to a leak. Sure if this was a bus of high or unknown mileage I would be all over swapping out for a good or rebuilt tranny. But under the circumstances just replacing the MS rear bearing is a wise choice. It is a simple no harm-no foul job. Will NOT hurt the transmission and if it fixes it great if not nothing lost but a little labor yanking the trans.

If any of you think that is absolutely ridiculous you are more then welcome to come stay in my garage, rebuild the entire trans yourself and buy all the new parts and bearings for me. That would just be dandy!
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Samba Member #95

[[email protected]]

87k, or 8700, that now means nothing when the damage has been done. It only took 1000 miles for your 60k mile Bus to destroy its mainshaft bearing running low on oil. It's not if, but what else has gotten severely worn in the trans in question. Is it something that will make noise long before it fails, giving you warning? Or is it something that's going to need towed home? Is it something that could easily be repaired now, or something that will render the trans scrap when it fails. This is the roulette, you get to play by ONLY replacing the mainshaft bearing. You have gotten the advice of 4 VW transaxle builders, that have torn down/rebuilt transaxles numbering in the 1000's. If you still are hell bent on replacing just the mainshaft bearing, have at it.

[TinCanFab]

We can debate for years about if it's a good idea to try replacing the bearing by itself or not. I tried it on my box, but mainly because I wanted practice taking boxes apart. I plan on learning more about them in the future and already going to build my own box on the side in the meantime....

BUT, there is no way you are just going to pop off the nosecone and replace it. The bearing is PRESSED onto the mainshaft and the OD is pressed into the gear carrier. Then, if you have a snap ring shaft, how are you going to compress the spring to release the snap ring? It's under a LOT of tension and if you're not carefull, you might end up with one flying into your eyeball.

Even then, there's no gaurantee the bearing is making all the noise by itself. It's a huge learning curve, I discovered both my shafts were on finger tight and then lock tabbed in place... Who knows what you'll find untill you get in there.
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[vwinnovator]

[Casting Timmy]

Here is someone else that just replaced the bearing.

Need help with trans noise or
http://www.thesamba.com/vw/forum/viewtopic.php?t=6...p;start=20

It looks like you need a lot of electrical wire to help make it happen!!

Personally I think that the main shaft bearing thing could have worked well years ago, but these transaxles have enough age and/or miles on them I would open it up. I've just started with rebuilding these, but most of the time you can do a lot of justice going in there and just cleaning it up.

I just recently cleaned an 091 diff that had the same dirty oil for years and it was amazing the different of cleaning it right and reassembling it.

A free read would be the IRS transaxle rebuild thread, you could also get Rick Long's Swing axle rebuild book if you want to spend some money. you should have the 4 bolt pinion bearing which won;t require the special socket, but would need a press and fork jig to do it. A fork jig can even be a cut up case and is preferred by some rebuilders as well since it has the reverse stop to it.

Those phenolic plugs of the early years do rot out and fall out with age. Be sure to get good gaskets if resealing it, those cheap kits are terrible and a Sabo gasket kit from Weddle is only a dollar or two more and infinitely better quality.

[gears]

FYI: The bus box has a pathetic mainshaft NEEDLE bearing that normally fails with low oil level even before the ball bearing fails. The 002 needle bearing isn't nearly as durable (and forgiving of low oil level) as the early 113 bearings.

In fact, we oil feed these whenever we can, just to get them to live with PROPER oil levels.

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aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com