Spring Sharkfest Report

​On February 27 we had a 928 gathering at Munk’s motors in Waterford.  It was the Spring Sharkfest.  Chris Braden and the crew at Munk’s welcomed the 928 community to do a tech session on a subject that is a big issue on 928s.  The topic was how to remove and replace a torque tube.  Adrian Bogaerts had a donor car that was in dire need of a torque tube replacement.
 
The 928 uses a transaxle layout (engine in front and transmission at the rear wheels) and uses a driveshaft supported in a 4” diameter tube with bearings to transmit the torque from the engine to the transmission.  

We show how to replace the torque tube on a 1987 928 S4 Auto. Team effort!

​This is what is commonly referred to as a torque tube.  It is not uncommon for the bearings to fail over time as they can get exposed to road salt, heat, and age.
 
I had previously diagnosed the issue in Adrian’s garage.  When he ran the car, it had a horrible grinding noise, but it was very hard to isolate.  I had a mechanic’s stethoscope and probed various sections of the car starting at the engine and worked my way back.  As soon as I placed the probe on the torque tube, it was clear that this was the issue.  There were some very noisy bearings and I could feel significant vibrations.
 
About 20 people showed up for the event and everyone was eager to lend a hand.  Rick Christian from Munk’s had already prepped the car by washing the underside and removing the exhaust.  This saved us a lot of time so thay when we started at 10AM, we were ready to get to work.  Dave Kowalewsky and I directed various volunteers to remove nuts and bolts and answered various questions along the way.

​The first order of business was to remove the lower bell housing cover.  Then, because this was an automatic transmission, we could choose to either remove the upper bell housing from the block, or alternatively, cut the short bracket that is normally used for mounting a clutch guide tube in 5-speeds.  Fortunately, the decision had already been made for us as the bracket had been previously been cut.  That saved us about an hour. 
 
While various people we loosening the front flex plate from the flywheel and loosening the torque tube from the front bell housing, I turned my attention to the rear.  We needed to loosen the transmission mounts to allow the transmission to slide back an inch or so.  This not only allowed the transmission to tilt, but it also gave us some clearance to get the torque tube out.
 
Everything was going smoothly, and by 11:30AM we had the torque tube out and on the floor.  It did not turn smoothly, so the diagnosis was spot on, but then it was at this point we noticed something else was very wrong.
 
On the transmission bell housing, the support bearings for the drive shaft to the torque converter had failed.  Only a few balls were left in the race, and most of them were no longer round.  There were metal shavings everywhere – presumably the remnants of the missing ball bearings.  Needles to say, the bearing had failed.
 
Luckily Adrian had the replacement bearings there for us to install, but we had a dickens of a time removing the snap ring that held them in place, and then had to scurry about to find a replacement.  Eric Bogaerts, Adrian’s son, was very resourceful and found the appropriate piece at a local hardware store.
 
This slowed us down a couple hours, but it was a good experience for all to see that you just never know what you’re getting into, until you’re into it.  We also had difficulty reinstalling the new torque tube as the rear coupler that receives the driveshaft was slight bent and required some persuasion with a large hammer.  Once we got it started, everything else went very smoothly.  By now, everyone had left, and it was just Dave Kowalewsky and Corwin, and me that were finishing it up.
 
It seemed that everyone had a good time getting their hands dirty and helping out. I think they also learned that this can be a DIY project if you take your time, and enlist some help from a friend or two.
 
A big thank you to Rick Christian and Chris Braden from Munk’s for all their help and support.  Although I’ve done this project on jack stands, it was really nice to use the lift and allow everyone to help out and see what was happening.
 
The 928 crew has a monthly beer night on the second Wednesday of each month from 7 PM to 10 PM at Sneakers Pub located at 22628 Woodward Ave., Ferndale, MI 48220.  Everyone is welcome to join.  If you would like to get on the 928 mailing list, drop me a line at andrewmolson@yahoo.com or call/text me at 734-837-7908.