bad hesitation/ slip

i have a 97 blazer 4.3 the tranny was just done about 9k miles ago. well from what i think it might be a torque converter but im not sure how they go out. the tranny doesnt really want to shift it has no power under load and it makes a 'supercharger' kind of noise all the time. the main reason i think it is the torque converter is when you gas it, its almost like a clutch is slipping it revs but doesnt go anywhere. from what ive said does anyone know or have ever had to deal with this problem.

if i give it alot of gas it jumps back and forth like when your first learning how to drive a stick...... but its a damn automatic

Is the check engine light on?

Have you tried manually shifting it to see if it will work any better?

check engine light apparently used to come on but now it doesnt and manually shifting it doesnt seem to help.

check engine light apparently used to come on but now it doesnt and manually shifting it doesnt seem to help.
I'd say take it back to the garage that rebulit your tranny.Sounds like the clutches inside the tranny might be slipping.?There is or was a torq converter solenoid plug somewhere on the side of ur tranny,might want to umplug it and run down the road to see if ur converter is "locking " in like its supposed to.