Clacking from drivetrain in 4LO

Now that I've been out on a few trails needing 4LO, I've noticed some looseness in the drivetrain manifested by the clacking heard in the videos below. It doesn't seem that much different than other old manual transmission vehicles I've had, but I'd like to get some other opinions.

I only had time to spend a few minutes checking underneath it; the front drive shaft has a modest amount of play which is more than the rear shaft has. The axle U-joints seem tight although I may not have been testing them properly.

Let me know if the videos don't post correctly.

Thanks in advance!

Thanks for the suggestion; that didn't cross my mind. I haven't touched the transfer case since I got the Jeep last year, but I'll start with that. Off to the service manual!

Apologies for the chrome tube bumpers. I'm planning on replacing them but there's just not much time for the hobby. When I do have time I'm on the trails. Probably this winter I'll have time for some projects.