how do you tell if your shocks are going bad? Vehicle: 2008 Yukon with ZW7 (self leveling NIVOMAT shocks)suspension package 80xxx miles Its hard for me to tell because im used to driving my Sierra with Z60 package and its a hell of a lot stiffer than my wifes Yukon. The only reason im questioning the shocks is I recently drove the Yuk to work and when I was going over a series of large speed bumps, when the rear would bounce coming off the speed bump I would hear a squeak. Speed going over was 0-5 mph. cheapest I can find them is $350/shock I want to make sure its bad first. Anyone know a good site to Order the NIVOMAT shocks that wont cost me both my arms and one leg right before Christmas? Thanks in advance.