i just had my tranny done through my dealer via insurance ( got rearended ,caused things to shift and grenade) i have no box,programmer or anything other than a muff & silencer ring delete. when i drive under load during shifts it like the conv is locked, then unlocks and revs up a bit ( similar to a slip but it's not slipping) then shifts . it would almost be like it's down shifting and then the conv is locking up. is this just the coverter locking after the shift?? it does this in all gears now, i am just paranoid about losing a tranny somewhere with my 5vr and kids in tow??

 

You no doubt have an issue. Take it back to whoever did the rebuild.