Getting the dreaded pinion bearing noise...
08-02-2013, 12:42 PM
#16
Burning Brakes
Thread Starter
the #1 rule when you fix part of a working system and don't fix the whole, is the good parts just help the bad stuff to fail sooner.
a transmission is a lot of equipment to move. and you want to play without having new problems... you shouldn't have one of these boxes apart without having the installer replace all the suspect bearings (not just the pinion bearing... bad bearings also cause added stress to other parts), synchros, (incl. all synchro rings/springs), input/output shaft seals, selector shaft seal/s, case gasket, all O-rings incl. selector shaft cover O-ring, updated 1-2 shift outer collar, and even gearsets (2nd and 3rd get pretty chewed up in a relatively short period).
btw, I have good 3~4 gearsets available if anyone needs....
trustworthy rebuilders who will do the job (including the dreaded pinion bearing) correctly;
Advanced Automotion - Corpus Christi, TX, 817 939-6761
contact: Scott Dewitt, http://www.advancedautomotion.com/
Catellus Engineering; Stow, MA, 617 306-0457
Contact; Kevin Gross kgross@connact.com.
California Motorsports CMS - Lake Havasu, AZ, 928 855-5755
contact: http://www.californiamotorsports.net/contact.htm
a transmission is a lot of equipment to move. and you want to play without having new problems... you shouldn't have one of these boxes apart without having the installer replace all the suspect bearings (not just the pinion bearing... bad bearings also cause added stress to other parts), synchros, (incl. all synchro rings/springs), input/output shaft seals, selector shaft seal/s, case gasket, all O-rings incl. selector shaft cover O-ring, updated 1-2 shift outer collar, and even gearsets (2nd and 3rd get pretty chewed up in a relatively short period).
btw, I have good 3~4 gearsets available if anyone needs....
trustworthy rebuilders who will do the job (including the dreaded pinion bearing) correctly;
Advanced Automotion - Corpus Christi, TX, 817 939-6761
contact: Scott Dewitt, http://www.advancedautomotion.com/
Catellus Engineering; Stow, MA, 617 306-0457
Contact; Kevin Gross kgross@connact.com.
California Motorsports CMS - Lake Havasu, AZ, 928 855-5755
contact: http://www.californiamotorsports.net/contact.htm
But I thought that in general, these gearboxes are very robust, and that the pinion bearing is a very specific weak spot caused by a specific problem (too much preload) that actually can be dealt with in isolation without having to rebuild the entire box. Especially in my case, where I always match revs when I downshift. I guess we'll have to see how things look when we get it apart.
08-02-2013, 01:11 PM
#17
Racer
That sucks Cloud. I am sort of in the same boat. I have one pinion whiny tranny sitting on my garage floor and my current one is starting to grind in 2nd. Now what!!!!!! Crap!
08-02-2013, 02:05 PM
#18
Burning Brakes
Thread Starter
the #1 rule when you fix part of a working system and don't fix the whole, is the good parts just help the bad stuff to fail sooner.
a transmission is a lot of equipment to move. and you want to play without having new problems... you shouldn't have one of these boxes apart without having the installer replace all the suspect bearings (not just the pinion bearing... bad bearings also cause added stress to other parts), synchros, (incl. all synchro rings/springs), input/output shaft seals, selector shaft seal/s, case gasket, all O-rings incl. selector shaft cover O-ring, updated 1-2 shift outer collar, and even gearsets (2nd and 3rd get pretty chewed up in a relatively short period).
btw, I have good 3~4 gearsets available if anyone needs....
trustworthy rebuilders who will do the job (including the dreaded pinion bearing) correctly;
Advanced Automotion - Corpus Christi, TX, 817 939-6761
contact: Scott Dewitt, http://www.advancedautomotion.com/
Catellus Engineering; Stow, MA, 617 306-0457
Contact; Kevin Gross kgross@connact.com.
California Motorsports CMS - Lake Havasu, AZ, 928 855-5755
contact: http://www.californiamotorsports.net/contact.htm
a transmission is a lot of equipment to move. and you want to play without having new problems... you shouldn't have one of these boxes apart without having the installer replace all the suspect bearings (not just the pinion bearing... bad bearings also cause added stress to other parts), synchros, (incl. all synchro rings/springs), input/output shaft seals, selector shaft seal/s, case gasket, all O-rings incl. selector shaft cover O-ring, updated 1-2 shift outer collar, and even gearsets (2nd and 3rd get pretty chewed up in a relatively short period).
btw, I have good 3~4 gearsets available if anyone needs....
trustworthy rebuilders who will do the job (including the dreaded pinion bearing) correctly;
Advanced Automotion - Corpus Christi, TX, 817 939-6761
contact: Scott Dewitt, http://www.advancedautomotion.com/
Catellus Engineering; Stow, MA, 617 306-0457
Contact; Kevin Gross kgross@connact.com.
California Motorsports CMS - Lake Havasu, AZ, 928 855-5755
contact: http://www.californiamotorsports.net/contact.htm
Just got off the phone with Scott from Advanced Automation. I was very impressed with his knowledge of these gearboxes and his understanding of the pinion bearing issue. He even offered to fly up to Austin to pick it up in his small plane! And his price is very reasonable - on the very low end of what I was expecting. Thanks very much for the recommendation.
08-02-2013, 03:22 PM
#19
Team Owner
Join Date: Oct 2009
Location: one thousand, five hundred miles north of Ft. Lauderdale for the summer.
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my pleasure. Scott, Kevin and Roger Brown (CMS, Lake Havasu, AZ) are 3 solid resources for rebuilds... Scott is very well liked in the GT40 kit car world where custom Audi units are utilized. back in like 2008, after contacting dozens of transmission shops about sourcing tall gears for the 968 and having no luck whatsoever, i was lucky enough to find Roger at CMS... to my astonishment he was pleased to inform me that he had just finished doing some research and had recently built a box using a .600 6th gear (from the Audi parts bin) for a customer with a V8 swap. he also pointed to the importance of running a tall *5th gear for proper cruising between 45~65 mph (way to go Roger)! some of these guys really get into their work.
one more thing to keep in mind when you have one of these apart.... the average person isn't very good at spotting parts that are midway to failure. you can be sure that Scott's trained eyes will save you a lot of money in the long run.
*being able minimize the "up-gap" between the stock 2nd and the taller 3rd and 4th gears (sourced from Scott) to achieve smooth transitions all the way to the high gear–happened thanks to the combined efforts of Roger, Scott and Kevin.
.
one more thing to keep in mind when you have one of these apart.... the average person isn't very good at spotting parts that are midway to failure. you can be sure that Scott's trained eyes will save you a lot of money in the long run.
*being able minimize the "up-gap" between the stock 2nd and the taller 3rd and 4th gears (sourced from Scott) to achieve smooth transitions all the way to the high gear–happened thanks to the combined efforts of Roger, Scott and Kevin.
.
Last edited by odurandina; 08-02-2013 at 04:06 PM.
08-10-2013, 01:09 AM
#22
Burning Brakes
Thread Starter
Well, that was a complete false alarm. I took it to a mechanic in town is reasonably familiar with the pinion bearing issues in these (and other) cars, and he told me the sound coming from the back is definitely not a failing pinion bearing. He told me that since I have a few of the rear panels out of the car, and I have a roll bar that's welded to the chassis, my car is transmitting sounds from sources like the transmission and even the road in a different fashion than a typical 968, and that the noise, while definitely noticeable, is nothing to worry about. What a relief! Maybe my apparent hot running condition will turn out to be nothing, too...