My car is a 90 350 iroc. The trans was toast and i just had it replaced with a 700 out of an 86 305. The mechanic checked out the new trans and installed it and everything seemed fine. When i first picked it up and started driving it i was surprised because it was shifting so soft i couldnt even feel it, but somewhat disregarded it because my old trans had a shift kit in it and this doesnt. Well i get about half way home and it all starts falling apart. If you accelerate slowly from a stop it wont shift till much later then it should and if you get on the throttle a bit so that it should be shifting where it wants to anyways it shifts so soft you cant feel it. Any ideas on what he might have messed up?

EDIT: also i checked the trans fluid when i got home and it was a little bit overfilled but not by too much.

 

My first guess, incorrectly adjusted TV cable.

 

just checked it and it was adjusted fine

 

Well, did you figure anything out yet??