i have a 2004 chevy silverado half ton 4x4 with quadra steer, last summer the fluid was changed in the rear end and shortly after [800 miles] i started getting clulking noises when making a turn, i returned to the dealer and they put there best mechanic on it, he added and additive to help the clutches release [their words] and after a few days the noises went away, well is has resufaced and i am not sure what the answer is because it does not happen all the time and the dealership is not to familar with quatra steer.
Any evidence of leaks? Check the level anyway just to be sure.
If it was mine, I’d drive it around a bit to get the lube circulated and then suction off a bit, strain it through a white coffee filter and see if there was any suspended material in the lube. If not, I’d suction the rest out and consult my owner’s manual to determine what the correct fluid was and if there was any additive for the clutch packs that was required. Then see if the noise was gone or not.
If you find particulate, then it would depend on your level of skill and experience as to what to do next. As a default, I’d start looking for a Chevy dealership that has experience with Quadrasteer…
Go to http://www.smartsynthetics.com/pdf/TSB-GM-steerable-rear-axles.pdf to see a tech bulletin on this topic. Discusses proper lubricants.