SnowyATX

So the car is in the shop for a what appears to be a failing/failed pilot bearing. As you can see from the picture below there is some scoring or burnishing on the torque tube input shaft. The car has only 18K miles. The dealer didn't have time today to inspect it but apparently there exist pass/fail tolerance measurements that have to be made (various diameter measurements in and outside the wear area). I normally have a manual set but haven't bitten the bullet yet on this car. Would anyone be inclined to help out a curious mechanical engineer by digging up the details in the repair manual and posting a photo? Not sure if the Z06 torque tube is same as the Stingray or not but one or both would be interesting.

Thread regarding noise that created the visit to the dealer is here: https://www.corvetteforum.com/forums...release-2.html

Thanks in advance!

SnowyATX

Bump

Rzepka_r

Hi there - I have a 2017 digital manual and looked through it and did some word searches in it today and couldn’t find anything regarding acceptable and/or condemning limits on the input shaft.

Its possible I missed it, but there didn’t seem to be anything in the manual regarding inspection of such.

Sorry I couldn’t help,
Rich

SnowyATX

Thanks for looking Rich. I'm definitely planning on giving them the twenty questions if GM tries to claim its OK.

Thanks again.

2019GSTX

Rick,
u try these guys?
maybe they know the specs, saw some threads where they repaired input shafts.


https://texasdrivetrainperformance.c...x.php/services

Rzepka_r

One thing you should look at closer when you are there next is, and maybe it’s just the photo, but the end chamfer doesn’t look concentric. The left side of the shaft in your photo appears to be the shaft diameter and about a 45 degree chamfer, but the right side of the photo seems to have a larger chamfer that starts into the shaft diameter earlier. I’d try to visually verify everything looks like it was machined correctly on the input shaft. No, the chamfer isn’t going to cause an issue, but if the chamfer is put on with any type of lathe, it has to be perfectly concentric unless something isn’t running true in the first place.

I had purchased a brand new heavy duty muncie before and the input shaft splines were cut off center, it wasn’t easy to notice at first, but once I explained it to the supplier, they agreed the set up must have gotten messed up.

Im not trying to lead you down a goose chase and I’ll have to read your other thread, but I would be somewhat curious on why you had the problem in the first place. If they just replace the pilot bearing and nothing else, you’ll have to hope the pilot bearing was the original cause or it might just happen again.

Hope this helps
Rich

SnowyATX

I agree it is odd that the chamfer looks the way it does. Maybe the end of the shaft wasn't cut off "straight" thus creating the strange shape???

They described that they need to make measurements between the burnished and polished sections which is a good start. However, how does that prove that there isn't a concentricity issue between the splined section and the bearing contact surface or better yet a wobble in the input shaft. In mind it doesn't. I'm not an expert but I have been remotely involved with machining as a mechanical engineer for 30yrs (holy crap has it been that long...graduated from University of Texas in '89).

If they try to use the same input shaft I'll make a personal visit and be asking lots of questions.

Thanks for your additional thoughts.

VinceBlack

Hi Torch, I too have to bring my Z06 into the dealership because of what I think is a faulty pilot bearing. What issues were you experiencing when you realized there was a problem? Is the dealership covering under warranty?

SnowyATX

A nasty noise when pulling away from a stop in 1st (and eventually 2nd or reverse). Started last August and started happening more and more often.

Listen to the noise in the video in post #26 here: https://www.corvetteforum.com/forums...release-2.html

Yes, it is under warranty.

VinceBlack

Oh wow, that's not good at all! Mine's different...I hear an ongoing faint grinding sound when my clutch is pressed in and the car is in gear. The sound goes away as soon as I take the car out of gear; also starting to get some pretty good clutch chatter over the last 6 weeks. I hope you get your car fixed in short order. Sorry I kinda highjacked your thread, just trying to get some idea of what's going on before I take it to the dealer.

3X2

Pull the shaft out of the tube. Look at the center gray plastic guide that is glued onto the shaft and see if there is any wear to it. It should be round. I've sen them so bad that they looked like a triangle. Also look at the rear guibo (sp?) joint for any rub marks. Look inside the tube for any wear marks where the center plastic guide rides. Replace as needed. I'd suggest a complete shaft if the tube is ok or a whole assembly if both show signs of wear.Somewhere I have a picture of the center support guide. I'll have to find it.

SnowyATX

Yeah, been there done that on my C5. The C7 is at the dealer and they replace the whole torque tube assembly so I'll never get to see the guts (or maybe I will). Still waiting for them to do some runout measurements and such today to see if I get a whole new one at GM's expense.