My Transmission Pinion Bearing Experience

[ryann]

This post will try to summarize my experience dealing with my noisy transmission.
My initial post about this led me to realize that this was not an isolated incident.

I've got an 03 Avant with 90000 miles. I'm very easy on cars. My 98 integra GS-R with 155k miles on it still has the original clutch. I've had a noise which slowly got worse and worse over the last 20k miles. At times I thought it was tire noise, or perhaps the normal noise made by an Audi's quattro system. There aren't many around here, and my audi is the only one I've ever even been in. I mentioned it to the dealer while under warranty and after checking it out, they said it was not a bearing, and just a normal noise. The noise seemed to be getting louder, but it was only after new tires and an alignment failed to change the noise that I suspected something more serious. I took it to the local mom-and-pop shop where we put it on a lift. Turning the front wheels made an obvious bearing rumble from the transmission.

No one in a several hundred mile radius was willing to even contemplate the fix, but I managed to find a shop willing to remove and replace the transmission for me. Being fairly handy, I studied the shop manual and decided to try the repair myself. A big part of this decision was watching the video I purchased from JH Motorsports. The video is of a 6 speed rebuild, but the web site claims the 5 speed is "slightly different". Since the transmission worked perfectly, I wouldn't have to take the gears completely apart just to replace the bearing.
I purchased the tools I was missing from their list of required tools on their 5 speed rebuild kit page. I didn't buy the kit, because I wanted to see what the inside of the tranny looked like before buying parts I might not need.

I got the transmission out and brought it home. The flywheel was in very good shape, so that was one less worry. The clutch had another 30k in it, but it would have been foolish not to replace it.
With the JH video on, I quickly realized that there were more than slight differences between the two transmissions. Not one to be dissuaded, I had at it anyways.
I pulled the magnet plug from the center diff and saw there was a great deal of metal on it:


I then took off the output shaft based on how I interpreted the JH video. It turns out that this was unnecessary. On the 5 speed I could simply unbolt the center diff from the rest of the transmission. A big breaker bar and extensions made this not too difficult.

With the center diff off, I could see that there was nothing wrong with the center diff. I then took of the main case.


With the main case, I could not only see that there was nothing wrong with the output bearing.


Although I couldn't see it, I could finally confirm that the problem was the pinion bearing. Now to get at it...
Giving up on the video, I turned back to the shop manual. I needed to get a bearing off to get the input shaft out. There's a clip behind this bearing which keeps the input shaft from coming out.


This is where I ran in to trouble.
According to the shop manual, this required a special VAG tool. I found the tool for over $300 which seemed a bit steep for something I'd never need again. I drove the transmission around to every transmission shop and machine shop in the county. None could think of a tool to get it out. I called and emailed JH Motorsports multiple times for help but got no reply. I also had some worries about setting the pinion depth. This requires some very specialized tools to do right, and added another level of uncertainty.

I would also like to mention that the list of tools required for the "JHM 01A 5-speed Trans Rebuild kit" seems to be the same as the tools needed for the 6 speed. In many cases they are not needed for the 5 speed. I have a number of new tools (mostly big sockets) I may never need.

Stuck, I decided to cut my losses, and ordered a used transmission. Although I don't think it had to be the exact same code (GBT), I couldn't find anything which specifically stated that other codes were 100% equivalent. I asked on the forums, but got no answer, so running out of time, I ordered another GBT from a yard in NY and a stock clutch from ECS.

At this point, I got an email back from JH motorsports asking for a picture of the bearing I was having trouble with. I sent them a picture, and finally got a response a month later after everything was done asking "Which part were you trying to remove again?".

I opened up the new (to me) transmission just to get an idea of it's condition. While the synchros were not as nice as mine, they seemed good enough so I cleaned up the magnets (using a stronger magnet) and put it back together.
I had it re-installed with the new clutch.
The results: The transmission feels fine, the noise is gone. I think the garage got some grease on the end of the axle since I started having problems with the right front ABS sensor. They're fixing this now.

I've been playing with my old transmission and managed to get it apart using a gear puller. In this way, I was able to get the output shaft off and see the cause of my problems. Here are some pictures of my transmission's pinion bearing with 90k miles on it.





While wheel bearings do go bad, there's no excuse for this in a transmission with this few miles. I don't know enough about bearings and metallurgy, but I would guess that these were defective from new. As much as I enjoy this car, if I were shopping for cars again an Audi wouldn't be on my list.

So, if anyone is interested in any GBT parts in very good conditions, or a center diff, send me a PM. If you have the means to replace a pinion bearing, you may even want the entire thing. I'd think that a GBT which has been taken apart and checked out should be worth $1500 once put back together. I'll make you a deal as I've got a $3k hole in my bank account due to this.

[vhstejskal]

Ryann, great follow up to the previous post. I was just recently looking back at trying to compile a parts list of things that would be needed to fix the pinion issue. Based on your findings it doesn't look promising. I agree this seems to be premature for something with only 90k as my car has just over 65k and I'm having the same issue.

A little after thought; I wonder how many people with the 6MT have the same problems with the pinion bearing? Could it be production date or a case of bad batches from the bearing supplier?

[dougyfresh]

Unless all the syncros and bearings are new in the 'rebuilt' GBT, you aren't going to get $1500 for it. Market rate is under $500 for a used 5spd quattro trans without any new parts in it.



What oil was used in that transmission? The pitting on the bearings looks like heat damage which could be caused by lack of lubrication. You should be using a synthetic gear oil such as Redline MT90.

A lot of the gears and items on the 5spd trans are pressed on and you need heat and cold to get them off. This is best left to a transmission specialist as most back-yard mechanics do not have the capacity to do such a thing.

[dougyfresh]

Stuck, I decided to cut my losses, and ordered a used transmission. Although I don't think it had to be the exact same code (GBT), I couldn't find anything which specifically stated that other codes were 100% equivalent. I asked on the forums, but got no answer, so running out of time, I ordered another GBT from a yard in NY and a stock clutch from ECS.

All 5spd quattro transmissions use the same final drive ratio and casing so they are all interchangable regardless of the code.

[Stubek]

I had two pinion bearings go out, first at about 40k and it was covered under warranty so I thought nothing of it. When the second one went out at about 85k, the quote from the dealer was $4,800 for a rebuild or a new tranny from Germany for $6k installed.
I checked with several shops, all wanted between $3-4k to pull the trans, rebuild and put it back in.
I finally found a shop to put in a trans from a wrecked A4 that I bought for $1,500 and they charged me $500 for the install. Everyone I talked to would not believe me it was that bearing until they drove it and heard it. They all said that bearing should be good for 150k miles and I was stock!

[Stubek]

All 5spd quattro transmissions use the same final drive ratio and casing so they are all interchangable regardless of the code.

Actually, I went through this with my tranny swap. There is some slight difference that is in the length and if you go with the non GBT, then your drive shaft is about 1/2 inch off.

[chrisjackd]

My second gear makes a weird noise (5 MT) One thing I am proud of is my 140,000 clutch. :)

[Spinnetti]

Not 100% sure as I'm second owner, but I think our B5 is still on the original clutch - 185k.....

On the other hand, I'm hearing bearing noise.. LR wheel for sure, but after that I suspect the trans is starting to get tired too..

[A4 TSCHUSS]

Actually, I went through this with my tranny swap. There is some slight difference that is in the length and if you go with the non GBT, then your drive shaft is about 1/2 inch off.

I have no clue what you are talking about, because like Doug said, they are identical. The difference of a B5 A4 transmission from 1997-2001 to a B6 transmission from 2002-2005 is a difference of axle flanges and the casting of the differential housing having a 3rd threaded bolt hole for the transmission mount. Other than that they are the same minus some little differences on the outer casting of the casing that has no bearing on it fitting or not.. Different years of the B5 transmissions either do or don't have the casted area that can be tapped for the 3rd bolt hole like the B6 on the diff mount, but the actual outer size of the casings are the same for the bell housing and the rear tail section of the transmission. There are different gear ratios in the B5 tranny for 4th and 5th gear to tell you another difference.

All of us that have high horsepower B6 1.8t A4s use older model B5 A4 1.8t transmission in our cars when ours break since they are very cheap and can be had for as low as $100 at a U-Pick salvage yard or a few hundred dollars from other salvage yards with listings on car-part.com (and then of course others who think they have gold and want triple that). I have 5 broken B5 A4 transmissions in my garage right now that I have ran in my B6, and they bolt up PERFECTLY. You only need to change the axle flanges out to the B6 flanges since they have a completely different bolt pattern and shape as well as smaller axle bolts, and then either tap the 3rd hole in the diff housing if it has the provision for it or swap out your B6 housing so you can have all 3 holes to bolt the transmission mount to.

GBT out of a B6, DWR or DJJ from a B5 or even the transmission from the 2.8 A4 all work perfectly fine in the B6 quattro 5 speed A4.

[ryann]

A transmission rebuild seems to go for $3500 to $4000 plus a core. A junkyard GBT transmission of completely unknown history sells for at least $1200 plus shipping. I'd love to have found one for $500. I know B5 transmissions go for much much less. I'd have gladly paid a bit extra to know that the used transmission was at least checked out, and in good condition. I know some people have synchro problems at lower mileage, but I've driven four cars 140k or more each in the last 24 years and they all shifted perfectly when I sold them. There's certainly a long term benefit to rev matching, double clutching (at times), and not downshifting into 1st until you are nearly stopped. An easily driven transmission should have no problem going 200k (barring bearing failure of course).

A new pinion bearing is well under $200.

I'd have to check, but any fluid put in the transmission would have been done so by the dealer so I assume it was OEM audi fluid. I don't know if changing the fluid is part of the standard scheduled maintenance.
I had the worry that perhaps all the oil had leaked out, but when I drained it, the volume was correct and there was no sign of leakage. I've put in Mobil 1 synthetic gear oil. I know there may be better choices, but this transmission is driven easily and it was available locally.

As to pressing things on and off, I've got access to a big hydraulic press as well as a -80 degC freezer. It usually makes getting bearings on easy.

My lingering confusion regarding transmissions isn't so much between a B6 and B5 transmissions, but between all the different 5 speed B6 transmissions. Why would Audi change the code if there weren't any differences? I was worried that my speedometer wouldn't work or some other unforeseen consequence.

In the hope of helping someone else trying to get the input shaft out but unable to remove the input bearing without the special VAG tool, I think you can get at the required circlip if you remove the ring gear.

Unless all the syncros and bearings are new in the 'rebuilt' GBT, you aren't going to get $1500 for it. Market rate is under $500 for a used 5spd quattro trans without any new parts in it.



What oil was used in that transmission? The pitting on the bearings looks like heat damage which could be caused by lack of lubrication. You should be using a synthetic gear oil such as Redline MT90.

A lot of the gears and items on the 5spd trans are pressed on and you need heat and cold to get them off. This is best left to a transmission specialist as most back-yard mechanics do not have the capacity to do such a thing.