Wolverine
Well-known member
(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 normally 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 motion rather than a perfectly round motion. 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 has decided that the problem must be the input shaft housing in the transmission. 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 18,000 miles ago. At this point, I just don’t have a clue. It sure seems like a clutch problem, but that issue is eliminated with the installation of the new clutch.
The current issue is that of finding the correct part. 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. According to GM, this has to be the correct part – 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 they changed so much over the years. No one he contacted was much help either.
It doesn’t seem to me that he is on the right track regarding the part 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. Thanks for your input - I really need an expert here.
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 normally 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 motion rather than a perfectly round motion. 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 has decided that the problem must be the input shaft housing in the transmission. 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 18,000 miles ago. At this point, I just don’t have a clue. It sure seems like a clutch problem, but that issue is eliminated with the installation of the new clutch.
The current issue is that of finding the correct part. 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. According to GM, this has to be the correct part – 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 they changed so much over the years. No one he contacted was much help either.
It doesn’t seem to me that he is on the right track regarding the part 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. Thanks for your input - I really need an expert here.
Also the Pilot bushing may need replaced... I found out through the years that GM replacement parts work best, all the hype with speed enhanced this or that usually come with a price and another issue. Years ago doing a bit of drag racing, the GM parts held up every bit as good as the aftermarket "race" parts .. IMHO
