This car has always had a problem with the 1-2 shift. When I got it, it had a B+M shift kit in it with the accumulator blocked. Needless to say the 1-2 was brutal. When I had it rebuilt, a Trans-go kit was installed and a different servo for the band but its not the corvette servo. The shift was reasonable, until the trans started to die. Lost the 3-4 clutches, what a shock right? So I had it rebuilt again. For a while the 1-2 was fine and now the 1-2 shift is just like was before, its like a rapid shudder in the trans under power during the shift. It vibrates the whole car. I had the valve body out before the last rebuild, made sure the valves moved freely and that there were no burrs or any funny stuff going on. Supposedly the separator plate was replaced (the B+M setup of course had holes messed with), but I cant say for certain that was really done. Under light power its fine, but bangs the shift a bit harder than it should and more than it did when it was originally rebuilt.

Sooo... any thoughts? I have a different core I'm going to build myself but I'm curious if anyone knows whats going on with this thing. Its not like I'm running 400hp through it. I think it has a line pressure problem or something going on with the servo rather than trying to put too much power through it.

Its an 86 trans, if it matters.

 

any "gear whine" ? Kinda sounds like the low/reverse planetary may be worn out. - Also, could have broke the 1-2 accumulator spring. If it broke and colapsed, the accum may be shimmed solid, much like the B&M spacers do. I've pulled mmore than 1 trans down that had a broken accum spring.

 

No gear whine. I know the planetaries were replaced first rebuild and were fine the second time around (not many miles).