I have the exact same issue like Reybeast on my 2017 f150 EB. Bought it in Mar 2017 and worked with the dealer for the whole April and May and they told me the truck may need a break-in time and the noise will go away after a while but it's been two years and I have been suffered with my new truck for the whole time.
Not only I got the big clunck at somewhere on the drvive shaft or the rear axle but I also experienced the same banging/clucking noise every time I am at around 30 to 40 mph and 4th or 5th gear and and when I let go my gas pedale to slow down and press on it again to speed up. Only happened at around 30-40mph and I couldn't find out why. Dealers are helpless. I also opened the case with Ford manufacture and they are worse than the dealer. They don't want to email me back and forth, they only want me to talk to them on the phone so they can cover up evidents I guess.

 

I just purchased my 2019 (F150 5.0 4x4 10speed) two weeks ago and had this clunk happened for the first time today.Talk about panic mode!! I will be contacting my dealership in the a.m.Kind of wish I would have gone with the six speed after reading this.I'll keep everyone posted.

 

My 2018 did this. My 2019 does this. My buddies 2019 does this. Make what you want of that.

 

I think this issue is tempature related since I didn’t notice it all winter and it’s happened the past two days since it’s been in the 70’s.

 

Try putting the parking brake on before you put the truck I to park before you turn it off. I've been doing that and don't really get the clunk unless I don't do that.

As far as the dealership and the sound, it is deemed as normal , you'll just be wasting your time

 

My brand new '19 3.5 4x4 does the clunk about 1/4 of the time. It's pretty loud and can be felt in the floor board. Does it whether the parking brake is set or not.

I'm no mechanic, but it reminds me of the sound of throwing a car in Park while still in motion. My best guess is that it's the transmission slamming itself into the parking pawl. Not a good thing.

 

I have the clunk. But I also bought extended warranty through Ford for what is it; 6 or 7 years or 125k miles. Mileage is correct not sure about the year limit. I know it's whatever comes first.

 

I'd be more curious if there are any that DON'T clunk, on warm starts haha

 

count me in. 2018 5.0 10spd XLT

 

Mine made the clunking noise. I stopped the clunk on warm start up by putting my truck into park, then letting my foot off the brake and letting the truck/transmission engage the parking pawls, then I apply the parking brake.