Troublesome Noise (1 Viewer)

[CHCP]

I've got a fairly new noise coming from either my H42 4 speed transmission or transfer case. 1978 FJ40 KCJA.
It's a pulsating wear noise, not a whine or definitive grind. It starts in third gear about 30 mph and gets louder
as the speed increases to 40 mph. Continues in fourth gear, not as loud but there. Stops on a coast. Hoping someone
has experienced this so I can either plan on swapping the trans with t case or just the t case. Oil levels are good.
Thanks for any help.

 

[ceylonfj40nut]

Check your drive shaft. Does it have play or not lubed?

 

[65swb45]

If you shift to fourth early, or shift to third late, does that make a difference?