1946 cj2a growl when i let off on accelerator

[Fergie1952]

I have a 46 CJ2a it has a growl when driving on hwy and i let off on acceleratol. It has a Dana 41 rear end. I not really a die hard mechanic, but a friend told me to drain the 90 wt gear oil and put a bottle of stp and refill with 90 wt. any thoughts

 

[Lumpy Grits]

:ww:

Great piece of Jeep history you have.
First-We need to know just where the 'growl' is coming from.
I would first check ALL fluid levels. If that ck's OK.
Then look for slop/play in your U-joints.
LG

 

[Posi]

Yes, on checking all fluids, and identifying where the sound is coming from.
Assuming you have the stock T-90 , has it ever popped out of second gear when you let off the accelerator pedal?