although I do not have the same truck or same brand that you have, I did have the same problems, I have a 1997 ford expedition Eddie Bauer with full air suspension. and the rear was shot, it would've been extremely expensive to repair the problem then I did some research where you can either upgrade to a whole new air ride suspension or you could look into an aftermarket suspension which is "coil over/shock" Front/back it varies on price for me I paid round $400.00 and change with 2-3 hours install. where as later on you can still add the air bags in if you still need them. considering you are driving a V8 I'm sure that you have better things to spend you money on then the dealership right??? I went through amazon and they were the cheapest for the full kit and extremely fast with any answers I had.
Replace or repair the air suspension?????? on 2003 GMC Envoy
by serp77 in Babb, MT on January 06, 2014
ANSWER by asksteevies on February 01, 2014
I thought they make regular shocks now that going place of bags that u could buy,cheaper..
On vehicles equipped with rear air springs, the air compressor may fail causing the rear suspension to sit low.
Air compressor for rear air springs fail, causing vehicle to sit very low every time car is turned off.