Engine and transfer case questions

[Soupermike]

Trying to help out 2 friends at the same time with different issues.
First with the engine, are 6.5 and 6.2 heads interchangeable?
Will everything on a 6.2 fit into a 6.5? Water pump and etc

2nd friend has a transfer case that keeps jumping out of 4H. Where should I look first? The linkage was loose but has been fixed.
Thanks
Mike

 

[Gcelevator]

In regards to the water pump, if 6.2 is V belts and 6.5 is serpentine belt. The rotation is inverted. The most experienced can correct me if iam wrong.

 

[Mogman]

As far as the transfer case there are no detents in the HMMWV transfer case shifter, it relies 100% on the detents in the transfer case to keep it in "gear", so precision adjustment of the shifter is not necessary.
So unless something is moving so much that it is knocking the transfer case out of H (unlikely) then it is in the transfer case.