what gear oil to use depends on the temps where you live. I used 90 wt and they only had one type of friction modifier at the parts store so i used it. It solved my cluncking instantly. I had to the same thing with the wifes all wheel drive honda after only 30,000 miles.

 

when u get that cover off and u find out if u do or dont have a posi and if u do make sure u put posi additives in with the fresh oil oh and do NOT use synthetic with any posi

 

Oh boy here we go again - more myth-information.

I use Royal Purple Max Gear (synthetic) with the friction modifier already mixed in.

Works great with the Dana Power-lok (Dodge/Dana factory limited slip - not a chebbie "posi") in the 1st Gen D70 4.10.