Changed the differential fluid the other day, have been wondering if I should have used some type of sealant on the threads?? No leaks yet, but there seemed to be some type of sealant on the threads...

 

I never have on any vehicle.

The fill plugs should not leak.

Maybe some people do.

 

I threw some Teflon tape on the threads of them just for good measure. I definitely don't think that it's necessary (seeing as the factory didn't have anything on there) but as I reached for my ratchet to tighten the plugs back in a roll of Teflon tape just happened to be right there and my thought was "eh, why not, can't hurt."

 

Yup, 1/4" teflon tape. I keep a roll in my bag of Jeep tools and use it every time I change the diff fluid.

 

no need. crank it down to 25 ft lbs and it will be good