It’s a characteristic of these trannies I think not necessarily a flaw or issue. I also notice if I don’t let the suspension fully settle if I’m doing a quick maneuver involving D to R or the other way around I can induce this clunk. For instance I typically back into my driveway sometimes someone’s right behind me & if I rush putting it into R after yanking the wheel around even if the truck has come to a stop if it’s rocking/bouncing around slightly just after it’ll do the clink, let it fully settle & pause 1-2 seconds before putting it into R or D then no problem.