ArcticWhite

I have found multiple threads on people that have had a vibration independent of drivetrain rotation occur at 2000rpm in their C7. This is NOT a torque converter or driveshaft issue as the vibration happens in neutral at 2000rpm when not moving and at 2000rpm in every gear. Since it is engine rpm dependent, I am thinking harmonic balancer, something causing balance not to be right on the rotating assembly, motor mount issue, or something else like the torque tube that this allowing the engine to send vibrations into the car that should not be transferred.

Of all the multiple threads, no one has posted that their problem was solved and what solved the problem. Is everyone just living with it?

If anyone has experienced this and fixed the problem, I'd love to hear what it was.

ArcticWhite

Best thing I can come up with is it appears vibration at 2000rpm is the torque tube, likely a bearing. Not looking forward to that job. On the bright side, good time to go in and upgrade the low pressure fuel pumps.

Old Yellow

Remember, the transmission is in the rear.
With a automatic trans the drive shaft spins at engine speed all the time.
With a manual trans, when the clutch is engaged, the drive shaft still turns at engine speed.
The only way you can rule out the drive shaft is with a manual trans in gear, and the clutch disengaged, while the car is stopped.

Ed

KenHorse

I don't believe that is accurate.

The clutch assembly is at the flywheel not the tranny so the drive shaft doesn't turn if the clutch is engaged.

I believe the same is true for the TC

VNAMVET

I've had this issue since day one (2017 A8 Z51) and now have driven 8,800 miles. It's never gotten worse and so I've just ignored it. I only feel it when in neutral, while bringing up the rpm to 1900 - 2000 rpm. I don't usually do this..only when I want to see if the vibrations are still there. While driving, I cannot feel it, but I know it's still there.
It (the tranny) also has a small "thunk" when coming to a stop every time. Both issues don't bother me as the tyranny still works. I'll only take it in when it breaks. Dealer has told me that both issues are normal.

ArcticWhite

Mine is an auto. When thinking about it I came to the conclusion the driveshaft is spinning all the time which makes it likely it is the torque tube. I'll be pulling the torque tube in the spring, making sure the bearings are good and that the crankshaft end play is in tolerance. I want to ha e piece of mind that that is good after hearing about all the issues with this destroying the crank thrust bearings.

My vibration isn't only when revving while stationary. It is noticable going through 2000rpm in every gear.

WelderGuy

The clutch is engaged when the pedal is up, so the drive shaft will turn at engine speed when the clutch is engaged.

With automatic transmissions, the drive shaft is connected to the flex-plate/flywheel, and it always turns at engine speed.

KenHorse

Point being is that the clutch assembly is forward, at the flywheel and not in the rear end by the tranny

madrob2020

Not knowing much at all with mechanical parts, I wondered how with the clutch ENGAGED (M7) the drive-shaft wouldn't be turning. Seems us M7s wouldn't be moving much!

Jmhornz71

OK I am a little confused and maybe its my old mind So to clarify the clutch assembly is at the flywheel with the clutch engaged the "driveshaft" turns and the car goes, with the clutch pedal depressed the clutch disengages and the "driveshaft" doesnt spin. so the only time the vibration would be felt in a manual would be with the car moving. Sorry if this is repetitious

KenHorse

Yes. Same for the C5 and C6

Old Yellow

Not true.
The drive shaft would also rotate when the clutch is engaged (pedal up) and the transmission was in neutral.
The drive shaft is between the engine mounted clutch and the rear mounted input shaft of the transmission.

ED

KenHorse

Pretty much what he said

markeaux

I'm on my 3rd torque tube (including the factory TT) in my 2019 A8 with 4200mi, and just within the last few days the 2K vibration reappeared. Not looking forward to having it back in the shop again for over 2+ weeks and am seriously questioning if I want to put up with this again, and again, and again ....

KenHorse

A4?

markeaux

Oops, A8! Fixed it above

WelderGuy

Your fix didn't work. It's still A4.

I'd LL that car. Sounds like they don't know what they're doing. Eventually they'll damage or destroy the bearings in the engine, if they haven't already.

COvert-red

No suggestion here, just a simple question from the cheap seats: Can any of these TT issues (bearings) be related to basic alignment of the drive train components? A TT seems like a very unlikely component to fail (or cause failures) unless they are so poorly manufactured that the failure rates would be endemic to the model.

My condolences to the OP. What a grand PITA, disappointment.

CO

markeaux

Today I talked directly with the GM Corvette Engineering Manager on this issue. They know what is causing it in LT1 applications: after a while the flexible rubber connector (I don't recall the exact name he used on this part) on the ends of the prop shaft may become loose "shortening" the shaft. As of two weeks ago (from the date of this reply) in production and replacement parts they started using the connector used in the LT4 in all models.

If you are encountering the other issue of "intermittent bearing noise" in the TT, that is an entirely different issue.

If you need to contact GM on any issue the preferred method is through Ask Tadge. If you do this before scheduling service they could possibly have the parts required to fix the issue(s) already at the dealer before you take it in, thus potentially saving many days of downtime.

ArcticWhite

Will there be a part number for the Z06 rubber connector? When I look up the parts, it appears the torque tube is one part and individual parts are not available.