Clunk noise tcase or transmission?

been chasing this clunk for awhile.
Having a clunk sound identical to a bad ujiont when accelerator is 1st pushed down and a clunk noise when you let up on accelerator.
Does it going from 1st to reverse with brakes on too and changing from gear to gear.
If I put it in 4x4 there's no knock sound, it goes away.
Ujionts are new.
I can feel the clunk in the stick shift,

is this a tcase problem or transmission problem?

both are working perfectly otherwise.

Had the rear end inspected by two different repair shops and both said the rear diff is fine.

 

How's your carrier bearing and motor mounts?

 

Single cab. No carrier bearing, mounts look fine, when you turn the drive shaft by hand you can hear the clunk and seems to be coming from tcase transmission area but noise travels to know for sure

 

Can you feel any rotating free play ?

This in one of those feels more from experience learned overtime.

This is with the truck in the air or on the ground?

As things age they do wear it does not take much slop to cause a clunk.

 

With it up in the air you can hear the clunk too when turning the driveshaft back and forth and sounds like it coming from the tcase but sound travels so it hard to tell.
I don’t want to replace the tcase case and find out it’s the transmission or something else

 

Transmission in gear T-case in neutral see what it does!!

 

Nothing happened because the tcase is disconnected but in reverse the transmission or tcase makes bears noises but no movement of course when the tcase is in neutral and transmission is in reverse only, when in forward gears no noise

 

I would need to look again just how much of the case still spins when in neutral .

 

Ok, it strange because reverse makes a lot of noise and the forward gears 1-5 makes zero noise

 

I guess if the chain has been streached it might?
It’s got 750,000 on that chain,
Is there a way to test or tell?

 

Pull the case and look about the only way.

Maybe leading with 750,000 miles on the case might have been good.

It has done well! Time for a complete over haul ?

 

I just don’t know if it’s the tcase or transmission