massive clunk/knock noise

[Scarsman]

Man! Sorry for your frustration. It drives me nuts that there are no real mechanics anymore. My dad taught me how to actually find problems and fix them. These days it seems all a mechanic can do is plug it into a computer. If that can't tell him what is wrong, then it just goes to random parts replacement. I honestly think they have a peg board in the back with part numbers all over it, and they throw darts at it to figure out what to try next.

Will it do it if you power brake it? That is hold the brakes on hard while in gear and give it some gas? Maybe hold some gas on it and shift it from drive to reverse and back. If it will then you could have someone look at moter and tranny mounts, frame crossmembers and things like that while you do it.

Could also be an internal issue in the tranny or T-case?