Loud "clunks" while in 4H - 2024 Lariat PB with 4,500 miles

[Xman]

Have had my F150 less than 6 weeks. Used 4A a few times off road with no issue the first 2 weeks. I've driven in 4H three times when running around the hunting lease the last couple of weeks. I don't need 4WD on the lease but noticed that the front tire tread doesn't get caked up with mud/sand like they do in 2H. Not a sound out of the drivetrain the first two times. Yesterday, I made a run to the lease after some heavy rains to make sure all the feeders were good for the next week and a half while I'm putting another 3,000+ miles on the truck going to Wyoming. This time in 4H, there were a few loud clunks while driving slowly less than 5 or 10 mph (my estimate is 5x, 2 were in quick succession). All, on dirt, grass, or gravel, most but not all while turning. Most were when I was electric only but at least one was with the engine running. Note, I was not moving when I did the switch to 4H this time but the clunks occurred well after engagement. The sound with felt vibration was like someone hit the drivetrain with a 5-pound hammer. It seemed to be right under the cab of the truck. After about 3 miles of driving, switched back to 2H and drove 65 miles home with no issue. I packed the truck when I got back home so I am ready to hit the road later this morning for the long haul ahead of me.

But then I woke in the middle of the night thinking, I may be new to 4WD, but those hammering clunks may not be normal. I've searched a few threads but didn't find any reports that I thought were similar. When I'm in WY next week, I will be 50 miles from the nearest town, at high elevations in fridge winter weather using 4A or 4H all the time. Not someplace to break-down.

Thanks in advance for your thoughts, experience, and suggestions. They will be much appreciated. I do not have the tow-haul package but the PBs come with the 3.73 rearend.

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[Xman]

I went out this morning, drove 2 miles in 4A, then got on gravel and shifted into 4H while rolling. Everything was quiet. I did turns and went in and out of 4H 2 more times. Could not duplicate.

Off I go.

 

[DEEPDOWN]

I maybe stating the obvious, but there is no differential action, between front and rear axles, so when turning the front wheels, particularly the outside front wheels are rotating rapidly, while the rears, are "pivoting". I NEVER use 4H (or 4L) on anything but deep snow, mud, or VERY loose gravel/sand. The fronts will try to spin the rears faster than they want to (if that makes sense). Use 4A most of the time in rain, light snow, grass (or even dry roads for maximum acceleration).

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