FJK

Need advice from trans guy who really knows his stuff. Here's the background: 88gta, 5.7L w/vortec supercharger, b&m shift kit in 700r4 trans; LOST 3rd & 4th gear(3rd acts like nuetral).
Before commiting to pulling the trans & rebuild, my son & I decided to drop the valve body & check out anything that might relate to the B&M shift kit. (Yes, we'll replace with Transgo). We found the 3/4 accumulator piston lands (surfaces adjacent to piston seal) to be heavily scored & gouged. The piston bore (in the case) is also scuffed & scratched, but not as bad as the piston. The seal ring in the piston appears OK. The questions are:
1) Can the piston & bore condition cause enough seal leakage to cause loosing 3/4 gear? Presumably, insufficent pressure to apply the 3/4 clutch?
2) Reguardless, can the bore in the trans case be repaired & how? sleeve kit? hone & oversize piston?

We really need the above questions answered to decide how to procede.
Thanks, FJK

Jay 727

To make this short the transgo 2&3 reprogramming kit has you put a plug in the 3-4 accumulator feed hole. I would assume with this modification you could leave the piston out. I wouldn't but my point is that it's not used with the hole plugged so it's condition wouldn't matter.

Pro Built Automatics

As stated, you plug the feed hole to the accumulator (4th gear only) & reinstall the spring & piston with the seal. It basically does nothing after that. If the bore is tore up it will allow oil to leak away from the 3-4 clutch apply piston, there in turn helping to burn the clutches. It will help burn the 2-4 band also. By blocking the accumulator it will firm up 4th gear and help the 2-4 band to live longer, and at the same time you will not have to replace the case.