Why does rear suspension system keep adjusting itself? on 2007 Buick Rainier

Vehicle is not sitting low like in some other cases mentioned. Also notice a clunking sound sometimes when going from one surface level to another, i.e. backing out of garage which has a lip onto the driveway. Sometimes sound comes from left front of vehicle, other times from rear right of vehicle.

by in Chester, VA on December 19, 2012
1 answer 2 comments
ANSWER by on December 20, 2012
poss air leak at bags or lines,very common and costly issue
COMMENT by on December 20, 2012
When you say "costly", what's a ballpark repair cost?
COMMENT by on December 20, 2012
if it needs everthing poss 1500.00