Re: Quadra Trac 2 Clunking Sound
My 2011 3.6 had the clunk from new and it hasn't really changed. I have complained about it at every service but the dealer doesn't have any solution. I also had the steering wheel clunk (TSB 19-004-11), which is now returning after it was successfully fixed with a new steering column shaft, plus other sounds and rattles which hasn't been fixed. I don't have the self leveling shocks which apparently also rattles a lot.
Your description of the clunk is good and I think the transfer case is the most likely cause. I believe we both have the MP3023 transfer case. Since you didn't have the clunk from new it does seem to be different from vehicle to vehicle though.
There is a STAR case S1121000013 about the 4wd system binding if there is a difference in rolling radius. My dealer referred to it and I have a paper copy. It is however not the cause of this bump/clunk which happens going straight out with no difference in rolling radius.