Sometimes when I start going down a hill slowly and NOT pressing the accelerator, the truck's transmission clunks hard...twice..when shifting to a higher gear. The clunks are load, hard and rapid. Does it the hardest betweem 3-4 and 4-5. This happens most of the time but there are times that the shift is smooth as silk. Any idea what's going on? (appointment with deal in 3 days. truck parked until then)

2022 F250
6.2L gas
Transmission - TorqShift®-G Six-Speed Automatic w/SelectShift® Automatic

 

I experience the same thing and have read similar articles with others having the same concerns and say it's somewhat normal for the 6-speed. Part of the issue maybe combined slack in the tranny as well as some driveshaft clunk.
I plan on removing the driveshaft and greasing the splines. I come from driving with the ZF6 manual so wasn't really an issue but greased the shaft regardless and made a big improvement.