I’m stationed in Germany and when I picked up my car I noticed the clutch starting to slip. My 92 has 86K miles so I figured ok... Time for a new clutch. I bring it to the GM dealership to do the dead. That’s where my trouble starts. First they put in a new clutch and give it back to me. The transition from clutch pedal to the floor to about half way out is WAY rough, I’m talking the whole car " SHAKES". I brought it back and explained. They thought new clutch was faulty so they order another one and It does the same thing. Now they tell me that I must buy a flywheel. $$$$ 1600 EURO. So I agree knowing that most vettes usually replace the flywheel and the clutch at the same time. They put it altogether and WOW amazingly it is still doing it. The vibration is a little less than the first time but still it is a big problem when driving especially when taking off from a stop and downshifting. Even when in neutral It makes noise. Could a fellow C4 enthusiast give me any tips?

 

1600 euros for a flywheel!!!? You can get an aluminum Fidanza one for around $400. Anyway sounds like you've got a severe clutch chatter. If it wasn't there before, then the dealership has created the problem. Chattering is caused by an uneven application of the clutch because the flywheel, disc or pressure plate is warped or misaligned. This was probably caused by some hamfisted dealership mechanic tightening everything with an impact gun. I would give the dealer 1 more chance to make it right, if not find a good mechanic.

Good Luck,Paul

 

Assuming your car has the ZF6 speed gearbox like mine there are a few things to consider.
1 The clutch and flywheel are both different than normal cars. The clutch does not have springs like normal clutches, instead it has a dual mass flywheel that has the shock absorption ( normally handled by the springs in a clutch) built in between the two pieces and this is what allows foe the smooth engagement. Look at the clutch they took out and compare it to the replacement clutch disc. There are normal sprung clutches that will fit but will cause enguagement problems.
2 A new dual mass flywheel has to be balanced to the old one as the LT 1 is externally balanced and if this step is left out there will be an additional vibration from the engine between 3000 and 4000 RPM due to this embalance.
3 If is the 6 speed the clutch and preassure plate should be replaced together as the dual mass flywheel's damping ability will soon wear out at 86K and yopu will have to do it all over again.
4. I know the shipping will be a killer but if you GOOGLE a company named Carolina Clutches they have the best price on the proper clutch/ dual mass flywheel and they will ship overseas.
5. Once you get the new flywheek you need to take the old one and the new one to a machine shop and have them "match balanced" in order to avoid creating a vibration in the engine.

I am thinking your mechanic put in the normal clutch with the springs and this is the cause of the problem.
I am recommending you change the flywheel and clutch (the clutch the mechanic put in may now be worn unevenly and could be a problem if you reuse it with the new flywheel. Add to this the amount of work involved in changing a clutch, it always makes sence to change both together.

 

Thanks for the information. Very helpful. Im going to take this information to the dealership and see just what he has to say. Yes i Do have the 6 -speed. I can almost guarantee they did not do any balancing of the flywheel. They have had my car for almost over 2 full months so im going to take this info and with a stern application and see if I can get something done...(right). Again thanks for the GOOD input.