My 1996 Blazer takes of in 2nd gear and shifts to 3rd and locks up the torque converter just fine but it doesn't take off in 1rst and it doesn't shift into overdrive. I replaced the 1-2, and the 3-4 shift solenoids but it didn't change anything. Whats next?

 

That's really strange.

Second gear is done by the band engaged and the 3-4 clutch disengaged.
Third is exactly the opposite - band disengaged, 3-4 clutch engaged.

I would say the drum could be damaged causing loss of functionality of the overdrive planetary, but then it would be shifting from second straight to fourth, or from first to third and bouncing off the rev limiter with too much pedal.

That's bizzare.

 

Shortly before it did what it's doing now, when it shifted from 1rst to 2nd it was a very harsh shift. Of course now it doesn't even start in 1rst now. At least I still have the equivelent to a powerglide transmission. ( sort of ! ) The computer codes it kicked out where for 1-2 and 3-4 shift solenoids electrical. also torque converter clutch circuit electrical. and tcc solenoid electical.