z06 Driveline Troubleshooting
 

I'm hoping to get some help diagnosing my issue before pulling the driveline out, although I think it's inevitable. Hopefully I can get an idea of parts I may need to order in advance.

2002 z06 all stock. 80k miles

Clutch grabbed fine, pedal works as it should.

I was getting vibration as RPMs increased. Vibration started around around 3k RPM and would get worse as RPMs pushed higher. If I would bring the RPMs up and press the clutch pedal the vibration would hang for a couple seconds then go away. It seemed to be completely RPM dependent and not better or worse with speed so pretty much the same for any gear.

No vibration when the clutch is depressed in gear or in neutral. With the clutch in I can rev the engine or hold 3k RPM and everything is healthy. if the clutch is engaged when sitting still the car would shake/vibrate lightly. Depress clutch pedal and vibration goes away.

Last week, something went wrong. As I was driving it to the my family shop to park it the drivetrain is making a grinding/whirring sound and RPMs pick up significantly if clutch is depressed and in gear OR in neutral. If the clutch is engaged and I'm moving there are no issues besides the previously mentioned vibration in higher RPMs.

Could this be a completely shot pilot bearing? I don't know what else it could be. Zero issues with the pedal. No slipping. No grinding of gears or anything like that when driving/shifting.

kinda sounds like the torque tube couplers might be shot

It sounds VERY much like the torque tube.. get couplers and bearings.

Does this sound like a coupler or bearing issue or both? I guess I'll be pulling it to find out but just curious sense you guys both went right to the issue being torque tube.

I've done a TON of searching on these torque tubes. Are there any write ups on how to rebuild? I believe I have 12mm couplers given it's an '02 Z. I see the kit on RPM is pretty pricey. Can the bearings be sourced anywhere else cheaper?

Can anyone send a link or PM a link for the BMW couplers? I've read good reviews about them and am wanting to go that route.

as far as bearings are concerned... I went with SKF bearings there is a thread with the part numbers in it if you do a search... I got them on Ebay for 75 bucks wfor all three... if your patient..... you could probably get them for even less.... I really like SKF we use them in our engines exclusively now.... http://evolution.skf.com/us/the-sky-is-the-limit/

Wouldn't poly cause more vibration in the drivetrain? I've swapped rubber bushings to poly in the past and it made the car shake and vibrate to the point it almost took the fun out of daily driving it.

Think about how the pilot bearing works, when the clutch pedal is out the crank and drive line are "locked" and the pilot bearing is not being used.

The only time the pilot bearing is "in use" is when the crank and the input shaft are rotating at different speeds IE clutch pedal in.

you are talking about suspension bushings...and possibly engine/trans mounts... whole different animal as far as vibration is concerned... this is a concentric rotating shaft.. the torque tube design does its best to amplify harmonics from the engine to the transmission. But most folks I know who have them as well as my own experience, this is not really an issue even with the slightly more dense poly...

I can tell you this much....if your torque tube bushings let go at 70mph its a wild ride :rofl:

IMHO,,,, DO NOT cheep out! Get the GM Rubber Couplers!!! Been down this road with a buddy and he had to do the job TWICE! He used the dorman replacements JUNK!! The BMW couplers are softer than the real GM Ones.

Bill

one other thing... if you go the poly route only use the drive shaft shop couplers... the Prothane "Six shooters" are not good... lots of failures documented here on the forum....

Right. So I understand the vibration under load with RPM that I've been experiencing sounds like torque tube couplers on the fritz. But now the "whirring noise" with the clutch disengaged (clutch pushed to the floor). It's also causing the rpms to increase when it should be idle. Couldn't that indicate a bad pilot?

There is ZERO chance that a pilot bearing can cause an increase in idle..... You have to rip it apart to get the TT off. Might as well pull the clutch apart and inspect. Better plan on installing a new Pilot just because they seldom survive disassembly.

Depending on mileage, I also recommend a new clutch

BC

:iagree: 80k I'd do the clutch, pilot bearing, new slave cylinder and remote bleeder if you don't have one. If the plans are to stay at stock power levels Luk or LS7 clutch, GM couplers and inspect all bearings.