I have a dana 60 under a car. it has been shortened and rebuilt.

I put the car in reverse and it tries to move. in neutral it unloads like it should. in drive it rocks forward then nothing. just free revs.

I blocked the wheels and looked under the car with it in drive and a friend on the brakes. the driveshaft was spinning, we rev it the DS spins faster the car won't move.

I pulled the diff cover and had it on the wheels, started the car and put it in gear. the diff is rotating like you expect to see it... except the wheels are not moving.

I pulled the axles and there is a TON of spline engagement. I can barely spin the driveshaft in neutral wheels on the ground and the car off, but i can get it to rotate.

So this means the diff is bad?????


Help

Also- is this a stock differential unit?