hello i have a 91 turbo 940 the right rear sits up at normal height but left rear sags and is about half inch above tire and right is about inch in half What would cause it to sag also when i go from a stop it rumbles in rear a little and when extra weight is in trunk it rumbles even worse any ideas

 

bad suspension bushing(s)?
badly worn shock (especially if its a nivomat autoleveler, I think those were mostly used on the wagons)
bent suspension components ?

the rumbling may be from the drive shaft U joints, or the center bearing, if the rear is sagging more, its exaggerated.