T56 noise/vibration issue - help identify possible causes
Thread Starter
Joined: Aug 2007
Posts: 2,456
Likes: 129
From: Where the Navy tells me to go
So, I thought I had narrowed the issue down to something on the output side of the tranny. I've just started prepping to rebuild a spare T56 that I had bought over the winter, but figured before I go down that path I would go ahead and let the dealer take a look at it. Turns out, my initial instinct was correct...
Tech said it had a bad front left wheel bearing. Even he said he's never heard a wheel bearing sound like that, but after a test drive he found the bearing was very hot with a thermal imager, then confirmed it with a mechanic's stethoscope.
During my own troubleshooting, I had used my IR pyrometer to try to find if any of the bearings were hot, but didn't get any conclusive results. I had also checked for play in all of the wheel bearings multiple times - jacked up in my driveway, and on the lift at the hobby shop on base. Nothing. After getting the car back from the dealer (told them not to fix the bearing, I'd do it myself) I checked for play one more time before replacing the wheel bearing. Still nothing - felt rock solid.
It was definitely toast, though. Came out in pieces, grease is all black/burnt, bearing feels very rough. Got the new bearing installed after work today, just took it for a test drive - good to go.
All this ******* time troubleshooting the drivetrain and it turned out to be a front wheel bearing.
It wasn't all a waste of time - the driver's axle inner CV definitely was bad, and I think the driver's rear wheel bearing was on its way to going bad, if it wasn't there already. But I could've fixed the main problem myself a few months ago; shoulda done the mechanic's stethoscope on the front wheel bearings when I was using it to listen to all the stuff in the rear end.
I've been having some driveline noise and vibration issues with my CTS-V. I think I initially noticed an issue back in the September/October time frame. I thought it was a wheel bearing (based on it sounding/behaving like bad wheel bearings I've had on my other cars), so I was working on that premise for to start out with.
During my own troubleshooting, I had used my IR pyrometer to try to find if any of the bearings were hot, but didn't get any conclusive results. I had also checked for play in all of the wheel bearings multiple times - jacked up in my driveway, and on the lift at the hobby shop on base. Nothing. After getting the car back from the dealer (told them not to fix the bearing, I'd do it myself) I checked for play one more time before replacing the wheel bearing. Still nothing - felt rock solid.
It was definitely toast, though. Came out in pieces, grease is all black/burnt, bearing feels very rough. Got the new bearing installed after work today, just took it for a test drive - good to go.
All this ******* time troubleshooting the drivetrain and it turned out to be a front wheel bearing.
It wasn't all a waste of time - the driver's axle inner CV definitely was bad, and I think the driver's rear wheel bearing was on its way to going bad, if it wasn't there already. But I could've fixed the main problem myself a few months ago; shoulda done the mechanic's stethoscope on the front wheel bearings when I was using it to listen to all the stuff in the rear end. 
