trans guys help

Ok guys here the thing.. I have a 85 z28 just put a 350 in it with a 700r4 trans. (trans was rebuiled) When the drive shaft was not in the car i was able to push it backwards and forward.Ok got the motor in trans drive shaft now the car will not roll back. Someone told me it could be the bands in the trans since it sat for awhile after the rebuild... So today got the car running filled the trans, drive works great. But and here comes the kicker. When u put it in reverse u can feel it go in but car does not move. it will if u give it alot of gas. its like one wheel is locked up or one is trying to go foward and the other back.. I'm thinking its the trans since u can push the car with the drive shaft out. What do u all thing???

if the tire is not draging it has to be that the trans is slipping i would take it and have it checked

don't know if you fixed it yet... but it sounds like incorrectly installed servos. the servos control when the kevlar band is engaged. the band is the only part of the 700r4 that prevents it from rotating (other than the parking lever).

imagine a spinning/rotating glass of water. you put your hand around the glass and squeeze to prevent it from spinning... thats what the band does. in your case, when u give the car enought gas, it makes enough power to overcome the force of the band.... and then move the car.

good news: you don't have to disassemble the trans completely to check the servos.

bad news: 1) you still have to take it out of the car. 2) if you're not sure the rebuild is done right, you'll want to disassemble everything anyway.

my reccomendation: check servos (you will need a diagram for this), put back in, try it out. if still doesnt work, recheck entire rebuild.