switched to RP 5w-20 today after 5000 miles. Gonna switch everything to RP just not sure if I should do it all at once or one at a time at different times.

 

I am planning on changing all of my fluids soon and want to use RP for transfer case. The owners manual says to use ATF, should I use RP Max ATF, or syncromax as mentioned above?

 

Yes you absolutely can use Max ATF in your transfer case. It is a direct replacement for the Chrysler ATF+4 fluid that Jeep/Chrysler puts in the transfer cases. The Synchromax fluid is formulated specifically to replace ATFs in manual transmissions and transfer cases and offers some oil film strength benefits, so is RP's preferred fluid.

 

hope that helps

 

I use Royal Purple in both my Lotus and the Jeep. I swear by it.

 

A Manual transmission needs just over 2 quarts...

 

Apart from breaking down slower under heat stress, I'm just wondering if synthetic oil has a better penetrating effect than mineral oil, or is this factor purely down to the weight rating of the oil; ie the thinner the oil the better the penetration (with all the talk here on this forum about spun bearings I'm wondering if the design of bottom end of the 3.8 V6 has led to lubrication issues)? I do know my motor is noticably smoother above 300RPM on full synthetic than mineral oil.

 

email RP and straighten them out

 

i use AMSOIL for the simple fact that it allows me to change the oil at 1-year intervals. That's usually about 15,000 miles. I have it checked by Blackstone laboratory at the 1-year level, and have it come back OK each time.

disclaimer:(most of my history with extended drain intervals have been on an Explorer and Tundra, but I'm expecting the same from the JK - i've only owned it for about 1200 mi.)