killav

I just read through this post, and I was also thinking about the rear flex plate at the Trans. But, with no 5 speed experience, I wasn't sure exactly how things are put together back there. I'll just say again, three or four knowledgable 928 guys were all looking at this part from my car and thought that there was no way this was causing the noise. Me included. But it was. The rivets seemed tight, but when I finally clamped the thing in a vice, the flex plate would move about 1/16 of an inch side to side. This was enough to cause the very annoying rattle in my car.

The thing is, a 5 speed car disengages the torque tube shaft when the clutch is depressed. But if the trans is in nuetral, with the clutch out, the torque tube shaft will spin at engine speed, correct? Is there a difference in the noise with the clutch depressed vs. having the trans in nuetral with the clutch out?

My rattle was impossible to localize. The sound eminated from everywhere, using the torque tube as a huge tuning fork.

killav

I just re-read your first post. In quick summary, when you depress the clutch, the noise goes away. This would stop the torque tube from spinning. Can somebody post a pic from the shop manuals showing the exploded view of the rear torque tube/trans assembly? It is my understanding that the rivets are an 87 issue only. I'm not even sure if there is a "flex plate" on the rear with a five speed. My rear flex plate bolted to the torque converter, which obviously is lacking in a 5 speed.

Bill Ball

Roger, you've got AT on the brain.

Right now I'm voting ball cup bushing because the release arm did move in and out loosely when we removed the slave cylinder rod. However, I have seen at least one 5-speed where the arm easily fell off the ball cup and when reassembled it did not rattle. There was enough tension with the rod installed on the arm that the arm was held in place. The same seems to be true for Matt. Still, we should replace the bushing and take it from there.

Charley B

Sure sounds like a classic bad throw out bearing. I haven't had the displeasure to hear a ball cup bushing going bad. Just a matter of time I suppose.

killav

Loose rear pinch bolt???

killav

Here is one other thing to try (if its not the ball cup bushing or rear pinch bolt or whatever). After checking the torque on the rear pinch bolt, leave the allen wrench in the cap screw. Take a rubber mallet, and tap the allen wrench in the direction of motor rotation. Don't kill it, just some light taps while keeping the wrench seated in the cap screw with your other hand. First, do this with the clutch engaged so that a load will be on the entire drive line. Next, put the E-brake on, put the car in first, have an assistant depress the clutch, and then try the rubber mallet again. This should help isolate the rattle to the front or back of the car. At least from the clutch forward, and clutch rearward. I did this with the drain bolt on my converter with the car in park and the e-brake on. Without all of the mechanical noise from the running engine, TT and trans, it helped me isolate where my noise was coming from.

ROG100

Well you learn something new about these cars everyday.
No rear flex plate on a stick shift.
Repeat 30 times before going to bed - no rear flex plate on a stick shift.

Vilhuer

No ****.

PS. Roger, read your emails if you haven't done already. Sorry about offtopic.

edco

I pulled the airbox off and can see it “Photo Attached” It dose not move around by hand. Unfortunately I’m by myself with no way to observe it while the clutch is being depressed. The cup bushing looks old and is discolored but it appears to be in ok shape on the outer rim.

AO

That's not your problem. Sorry.

Bill Ball

Darn.

ROG100

What about the rear flex plate?

ROG100

It is still possible that the bush has disintegrated within the cup leaving only the outer part in place.
The one I did at the weekend seemed OK until I started to move the arm about trying to remove the clutch assy. The bush was in a hundred little pieces.

edco

Thanks Roger,

I’ll try to take a look at it when I have someone to push the clutch. I was hoping when we had it on Bill lift it would be easy to spot. Looks like a tough one as it’s too expensive to troubleshoot with parts. Doh more down time….

Thanks for all the ideas

Shark Attack

I had a car that did this.. it was the flywheel was broken around the bolt holes.. No not a 928.. I am ashamed to say a 89 LeBaron turbo