Drivetrain Noise

Just got my 1960 cj5 driving! Something in the drivetrain is making a horrible noise in 3rd gear, only when cruising steady throttle. It stops when accelerating and decelerating. No vibration. I changed oil in both the trans and transfer case, fluid looked normal, but the noise didn’t change. Any clues?

 

The most common problem with these is a worn out transfer case intermediate shaft bearing. Not sure that your symptoms match, but others will comment.

 

I seem to recall a thread where someone had this same issue..."sounds like a small child banging on something with a hammer"...only in 3rd gear. It turned out to be something like the shift cane rattling against something in the 3rd gear position?? I will see if I can find it...

**edit** Found it...

CJ3A Volkswagon TDI

If not the same cause, might be worth looking at some of the responses/suggestions.