1988 GMC Sierra Transmission Problems?

[josh]

I have a 1988 GMC Sierra truck with a 350 V8 Engine. The transmission sometimes slips, and sometimes will not go into second gear at high rpms. Im wondering what would be the best option to fix this, and what a ballpark cost would be like.

Thanks in Advance,

 

[sca_3]

First thing to check is your modulator valve. If it is a th350, it will be on the back rt side of transmission. If it ia th400 it will be on rt side of transmission. If it's a th700r4, there will be no modulator valve and trans pan has 16 bolts in it. When you described what was going on, I would suspect modulator valve because demand for vacuum shifting to 2nd. It is losing vacuum. I would also replace the vacuum hose as well. If that doesn't fix it, change fluid and filter. I hope this helps. Good luck.

 

[texaswildman]

i don't know where you are going to take it to. but it will cost you 1,200 us dollars. good luck. unless you know some people. maybe less.