Its kind of a clunk noise. I have BTS trans with 220k on it with regular fluid changes. Currently using Royal Purple ATF. Truck has 310k on it with no rearend work or universal joint replacements other than that middle drive shaft support dealybob. To avoid clunk takeoff, I have to ease on pedal which I do. My guess is to check rearend first and maybe replace u-joints since they most likely need it. Anything about TC or Trans, I have no idea.