i'm new at the forum but have found alot of useful info. I have a 95 blazer and the transmission wont shift out of first unless i run it up to about 3000 rpm then let it fall back to around 2000 and pat the pedal. the trouble started when i drove in overdrive it would try to shift in and out of od really fast back and fourth, i changed the filter and fluid and it did alright for about two weeks and now this started happening. Anyone who can help or that has any suggestions will be greatly appericiated.in the meantime you guys have a great site here, keep helping the chevy guys stick together

 

I'd check out the MAP sensor seein' as how that directly affects the shifting pattern of the tranny... might need cleaned or could be leaking at the gasket on the manifold.

 

and if that doesn't work, I would suspect dirt in the tv valve. Unfortunately the only way to fix that is to drop the pan, and the valve body. Its doable, but not for someone who doesn't have much mechanical expierence.

Does it downshift fine?
Hows the tranny fluid level? Checking it with the engine running?
Did you put gasket sealer on the tranny pan gasket when you put it back together?