I had this repeatedly happening on my 18' 5.0. Haven't had it happen once in my 20' 3.5.

 

I have a 2019 screw cab 4x4 19 speed. After 2.5 years of complaining the my service advisor finally caved and had the hydraulic shift thing replaced and something else under my extended warranty. This fixed the downshifting bang but did not fix the rear end clunk. I'm hoping to find a solution on this thread

 

Change the rear yoke, and it doesn't do it any more..

 

The "clunk" you describe happens usually when engine is warm, has been shut down for a short period of time and you return to start it up again. ??? Its the driveshaft, it jerks upon startup from a short trip usually when engine is warm. Try and have someone look at your driveshaft when your engine is still warm (shut it off and then on again).

 

There was a TSB for my old truck (a 2013) to address excess driveline lash in the pinion gear of the rear diff. Basically, they just loosened it, gave it a slight adjustment and tightened it back up. It helped 50% I'd say. I wonder if the same condition exists on 13th gens?

I don't know if just me but shifting from P to R or D or any order of those is pretty harsh. Sometimes it causes the truck to lurch at an unexpected speed. Almost as if the idle speed is too high. I think this is exacerbating the issue for me as the noise is quite loud and often has a "clang" noise mixed with the "thunk".
I'm digressing now but the opposite sometimes happens as well. If I'm in D and shift to R it often takes a (relatively) long time to for the driveline to start moving in reverse. During that time it acts like neutral which can be startling if you're pointed downhill.

 

Hey reybeast,
Your name seems to pop-up the most regarding the single "clunk" that occurs when starting an F-150 with the 10-speed transmission. Were you ever able to get satisfaction from Ford regarding the issue?
I bought a used 2019 F-150 in June 2020. Mine has done the same thing periodically since then. The dealer claims they never hear it when it's been in for service.
Right now, it's at the dealer because of a slight, repeating, "thumping" noise that occurs when rolling at a low speed (under 5mph). They replaced the rear differential and bearings, but the noise persists. They now think it's the transfer case because they found "metal" in the fluid. I'm trying to determine if the problem is linked to the "clunk" noise at start-up.
Please let me know.
Thanks!
Ted

 

Have there been any failures attributed to this “clunk”? My 2018 5.0 still does it periodically. I’m at 119,000mi. Had my transmission replaced at around 90k I think it was. It seems to happen when I don’t allow the truck to settle after putting it in park.

 

I have an 18, I just let it settle before putting it in park. Never had any issues. I also had the rear yoke replaced.