Tranny Probs. 93 1500

I have a 93 chev 1500, 305 engine and i assume the 4l60-e tranny.
The other day i was having problems with the truck quiting on me. IT would start then stop when is was warm and not start again for a few hours. I ended up replacing the dristibutor cap, rotor, ignition coil and the module that is under all that. lol not sure what it's called (maybe the pick up coil). Anyways it started right up and i took it for a drive. I noticed that it didn't have much power so we checked to see if the timing was right and it is. So i took it down the road and realized that if you start out in drive it doens't ever shift. You can manually shift down to second but when you shift down to 1st or up to overdrive is does not shift. So basically i am stuck driving in 2nd and 3rd (and manually at that). I am trying to cover all my options before accusing it on the tranny. Do you know of anything i can try. I heard that this can happen on some 99's and you can reset some module thing but i dunno about back in 93. Any help is apreciated
thanks
Chris