Justin01SS

Hello all.

When I bought my 03 Z about 3 years ago, it had a whining noise that sounded like transmission or rear end whine. After fixing the bearings inside the transmission and finding it did not fix the problem, we stumbled on the front of the torque tube having a chewed up bearing (if memory serves, its the bearing I have pointed out below). To fix it, I bought a used 04 Z torque tube and replaced it. Issue seemed to be fixed, whine went away.

About a year ago, the noise started to come back again and sounds very similar to the noise from the last torque tube issue. Seems rather odd to me why the car would be going through this particular bearing. Any ideas on what could be causing this before I have a shop tear into it again and verify if its the same bearing? The labor to take these out are rediculous so I'd like to have an idea on what needs fixed or if I should just put another torque tube in and cross my fingers.

Thanks for the help!
Justin

SaberD

i have read a lot of posts where the torque tube bushing bolts get bent or even broken. this could be the issue. this can cause the bushings to get eaten up due to excessive vibration causing and also causing premature bearing failure. These bent/broken bolts were even torqued to the stock specs. i think a lot of people solved the problem by using stronger bolts than the stock ones. also, never reuse the old bolts. just my theory.

LSx Believer

I've never heard of this but it seems that if the pilot bearing were worn out or missing it would put more pressure on the torque tube bearing. I'm not saying this is your problem. It's just a thought.

LoneStarFRC

I was thinking the same thing too, or at least allowing runout or wobble on the input shaft (splined shaft).

Also, why would you consider replacing the torque tube and not just address the affected parts?

All_Motor_C5LS6

I was thinking the same

Justin01SS

I've read a bit about these torque tubes not being the best design in the world, so wasn't sure if it was happenstance or maybe just bad installation. I wasn't sold on this fact, just a thought.

So the pilot bearing affects the shaft that comes out of the torque tube where that bearing is located? Forgive my stupidity when it comes to that. Any other ideas on what I might look for? This has been very helpful by the way!

LoneStarFRC

Think of the (splined) "input" shaft this way: if the shaft is basically a single piece of metal that is supported at each end by a bearing in order for it to run true, then what might happen if either one of those two bearings were to fail and cause the shaft to no longer be supported at each end and allow one end to wobble? Might not it cause the bearing at the other end to have undue stresses placed on it too?
I'm not necessarily saying this is the absolute cause of your problem, but it makes sense to at least check it out as a strong candidate.

Btw, the reason I refer to the "input" shaft in quotations as well as calling it the "splined shaft" (GM calls it "propeller shaft, splined shaft") is only for clarity. As you know, on a C5, the transmission is located behind the prop shaft and it's "input shaft" does not fit directly into the pilot bearing on the crankshaft like a conventional transmission layout. The shaft we're speaking of here still serves the same purpose however, it's just the location of the components is completely different than say, the F-body cars for example.

There are now quite a wide variety of individual replacement parts available for the driveshaft (prop shaft) and even some on the torque tube assembly itself as well. A number of years ago, GM did not offer any replacement parts for the driveshaft itself (not even the couplers) and only sold a complete replacement driveshaft assembly, or the complete torque tube assembly.

Either get it out and inspect everything (inside and out) or have a competent shop do it. Considering how cheap a new pilot bearing is, put a new one in as well.