The only stuff im finding is from the early trucks before all the ECM updates that helped fixed that for the injector and timing knock. They've gone through quite a few revisions since 17 from what i found.
as for tsb's, i honestly dont see any for a 2020 for "thumping". the only ones i found similar are the ones in the purple that i clicked on. they just state about misfire codes and how to diag or the other is about the DEF tick i already stated and possibly the decel rattle but the decel rattle will only occur once during a key cycle (if you even hear it) per the fuction GM has programmed into the ecm so the injector timing for each individual injector is set. if the rattle continues after one cycle and no key cycles between, its not the active decel injector timing. as ive said, ive never heard it till the DPF died and the others ive driven or rode in have not done it. are there some out there that make noise? most likely. do they have the most up to date ecm software? how many miles are on them now? are they running any kind of tuning? how healthy is the fuel system? are there any other systems that are not happy attributing to the tick or rattle being heard? all variables but im not saying it cant happen. at the end of the day, these are still miles quieter than a LBZ. the fact the dpf made the injectors so sensitive on my truck shows how everything needs to play nice. you cant run these trucks into the ground, goes for all ford, dodge, and others.
as for tsb's, i honestly dont see any for a 2020 for "thumping". the only ones i found similar are the ones in the purple that i clicked on. they just state about misfire codes and how to diag or the other is about the DEF tick i already stated and possibly the decel rattle but the decel rattle will only occur once during a key cycle (if you even hear it) per the fuction GM has programmed into the ecm so the injector timing for each individual injector is set. if the rattle continues after one cycle and no key cycles between, its not the active decel injector timing. as ive said, ive never heard it till the DPF died and the others ive driven or rode in have not done it. are there some out there that make noise? most likely. do they have the most up to date ecm software? how many miles are on them now? are they running any kind of tuning? how healthy is the fuel system? are there any other systems that are not happy attributing to the tick or rattle being heard? all variables but im not saying it cant happen. at the end of the day, these are still miles quieter than a LBZ. the fact the dpf made the injectors so sensitive on my truck shows how everything needs to play nice. you cant run these trucks into the ground, goes for all ford, dodge, and others.