A friend of mine has a 79 C10 pick up that just had the 620HP GM 572 installed in it. He also had the factory TH400 rebuilt by a local trans shop to supposedly handle 1000HP. He put roughly 15 miles on the truck and drove it like a little old lady, (I was following him so I know). Anyway when he went to take it and try it out the trans didn't feel right so he drove it over to my place and took me for a drive. The transmission was slipping horribly, it didn't feel too bad in 1st gear but 2nd and 3rd were just slushy feeling. So he loaded it on a trailer and took it back to the trans shop. They pulled it apart and said all the clutches were toasted like it had 200,000 miles on it. Now they are telling him that his engine only has 7" of vacuum and that isn't enough and the line pressure is too high (around 200psi) and it will take out the thrust bearing on the crank. They are now going to put in a 4L80E trans of his that was at my house awaiting another one of his projects . I'm not a trans expert by no means but the story from the trans shop sounds fishy to me. I phoned the trans shop myself to see what the owner had to say and he gave me the story of how the vacuum is so low that the line pressure won't go below 200psi and no one makes an adjustable line pressure regulator. I told him I was sure Kilgore makes one. He also told me about the thrust bearing issue. How can the trans push on the thrust bearing unless the convertor balloons up? I really don't think he knows what he's talking about, but I wanted some of you guy's input. Does this mean I better not put a TH400 in my low compression 454 with a big cam? My vaccuum is low too. Is it going to take out my thrust bearing? Something isn't adding up here. Thanks for any input.
John
John
