I just rebuilt the transmission to my 99 trans am a in feburary and it was working fine for a few weeks but now when i put it in drive it strugles to move forward and when i put it in 1 it does not work but when put it in 2 it starts going fine same with 3 and then finally i put it in drive i dont think its the clutches they are brand new i herd it could be the accumulator i did not replace the stock one i herd on 98 and up they tend to crack since they are plastic well any help will be greatly apreciated.

 

Tell us a little about your build? Shift kit? Stall?

 

yea i bought the monster in a box kit from monster transmission it came with a shift kit and everything i was a student at uti at the time that i rebuilt it. and i still have the stock converter

 

Its sounds like limp mode with the transgo kit. This will cause manual first to be like the brake is on. You will be able to use manual 2nd and 3rd no fourth and no lockup. No auto shifts and starts in 3rd gear in D3 nad OD positions.
Check fuses and the harness plug and wiring to trans, Then scan for codes. Its likley just and electrical issue.