Hi!

As the title states, I'm experiencing a terrible shuddering on takeoff once the car is warmed up. It takes off in first just fine when it's been sitting for a few hours. Also, once it's warmed up and shuddering, I can only get it to take off smoothly if I bring the RPM up to about 15-1700. I'm trying to break down the options as best I can. This is an 83 trans am with a mechanical clutch linkage. Newer engine with about 50k miles so I can't suspect a RMS leaking oil onto the flywheel when it's warm, though it's possible I guess. The flywheel is a new cast iron cheapo to spec but it worked perfectly fine during the first few months of driving this year. New RAM clutch 98730 Powergrip. Transmission is the old crappy T5.

When the old engine/flywheel/clutch was in, it shuddered even worse whether it was warm or cold and it shuddered going into 2nd gear. I thought the new flywheel fixed the problem because the old one was pitted and junk. The new stuff fixed it for a while.

The mechanical linkage bracket right outside the firewall had broken once before and it had been ******* welded back in, so the angle or whatever is probably slightly off which might hinder complete motion of the pushrod. But I don't see why it would be affected when it's warm and not cold. Maybe something to do with the heat causing some part to expand when it's hot and hinder complete motion?

I have yet to check the transmission fluid level and I supposed I could try flushing it and using new fluid. Is the fluid a possibility? Or maybe an internal aspect of the transmission? Mounts? Fluid leaking onto the flywheel? Clutch? Pilot bushing/bearing? Flex plate/pressure plate? I suppose since this is a higher level clutch, it might grab harder once friction has built up enough heat for those conditions to occur?

I just don't know where to start or even what the best plan of action would be, I'd like some help from someone with more experience than me! I've been planning on doing a hydraulic clutch conversion soon too, so I want to make sure this shuddering problem (or the nature of it) is figured out. I could be an idiot and this could be incredibly simple, but I'm young and learning! Thanks! And apologies for any grammatical/spelling errors in this, it's late and I'm a little tired!

 

That's your primary problem, right there.

What's happening is, when the engine applies some torque, it shifts itself a bit in the "frame", which changes the clutch linkage position, which takes the torque off, which lets the motor settle back down, which re-applies the clutch, which torques the engine up, which changes the clutch linkage position, which takes the torque off, which lets the motor settle back down, which re-applies the clutch, which torques the engine up, .... you get the picture.

Try new motor mounts. Hold the engine in its place. Hopefully you don't also have a broken Z-bar, as that's a VERY common failure in that old crap you've got.

I'd also HIGHLY recommend getting rid of that crappy old Stone Age linkage crap. That was the 2nd mod I did to my 83 (after a better shifter), in about 86 or 87 I guess, the VERY FIRST time I saw a 84 in the buzzard nest with the hyd setup. AMAZING how much better it is than that old crap.