[Black]

i put 1989 thunderbird coupe rearend in 1985 mustang gt and the back of the car lets up and down when i hit a bump can you tell me what the problem is i haven't changed anything

 

[scholman]

Black,

I guess I do not understand the question. What do you mean by " the car lets up and down when I hit a bump".....

What is the car doing or not doing that it wasn't doing before you changed the rearend?

Scholman