(sorry for the long thread)
I really need some expert advice about the 4-speed transmission/clutch on my ‘76 L-82. The symptom is that when the clutch is at the friction point, I hear a high speed whine, sort of like an electric drill on metal. When the clutch has been fully engaged for more than a few seconds I get the same noise, only at a lower pitch and slower. There are otherwise no symptoms. It shifts ok and sounds perfectly normal with the gears engaged.

Both my mechanic and I felt that the problem was with the throw-out bearing. He replaced the bearing and the entire clutch assembly while he was at it. The bearing did appear to be bad. The inner part of the bearing spun in an oval direction rather than perfectly round. He put everything back together and the clutch worked perfectly – for about a day. Within 30 miles it sounded just like before.

He took everything apart again and intends to replace the input shaft housing on the transmission (this is his best guess). Does this sound like the likely problem? Is there anything else that it is more likely to be? By the way, the trans was rebuilt 3 years ago. At this point, I just don’t have a clue. It sure seems like a clutch problem, but that possibility is eliminated with the installation of the new clutch.

The current issue is that of finding a replacement input shaft housing for the transmission. I have a Borg Warner transmission # 13-04-066-901. The bad part is stamped T89C-6A. They thought they located the part, - for the BW transmission -but it doesn’t fit. GM swears that they sent the correct part for the BW – if it doesn’t fit, they are telling us that we have a Muncie trans. and that the high performance package in ’76 used a Muncie. Clearly this is not the case, but my mechanic ordered the input shaft housing for the Muncie anyway hoping that it would be the right part. He was not able to make any sense out of the parts catalogues because the parts numbers changed so much over the years.

It doesn’t seem to me that he is on the right track and I hope there is an expert on the forum who is knowledgeable on the diagnosis and how to go about ordering the correct part, or what part(s) to replace so that we don't have to go thru this again. Thanks for your input. I really need an expert here.

 

A couple of things. 1) it could be a bad pilot bushing or bearing in the block (depending on what you have); or 2) there might be some mis-alignment going on with the clutch. The throw out bearing would have been my first guess also. There are probably a dozen or so other things it could be, possibly a defective clutch disc or pressure plate.

 

or a clutch Release fork

 

If the pilot were bad, you'd get some chatter. How does it shift?

I doubt the bearing retainer is the problem unless it's the wrong one to begin with. But take a look,..see if it's grooved out.

Also, look at your pressure plate and disc,..look for rub marks. I've heard of flywheel bolts coming in contact with the disc or perhaps something else is interfering with the rotation of the assy.

Lastly,..there two different TO bearings,..a long and a short,..are you sure you're using the right one (probably short)?

 

Thanks for your responses, guys. I got the car back last night and thought I would let you know how it turned out. I guess I should trust my mechanic - he replaced the input shaft housing on the trans and put everything back together. By comparing the new part to the one he replaced, it seemed pretty clear to him that the old one was bad. Anyway, the car runs perfectly and I'm pretty happy.

 

Well thats a good result. Glad it worked out.