Anyone run full synthetic fluids? Oil, Diff Fluid, Transfer Case, etc. Any problems?

 

I run Royal Purple and have had no problems. It's nice in the rear diff because you don't have to add anything for the limited slip.

 

Yep, lots of us. Plenty of threads on this already. Royal Purple, Amsoil and Mobil 1 are popular.

Amsoil also sponsored an 'independant' study of 8 or 10 leading brands that you can find through their website. Pretty informative, though who knows just how impartial it was.

 

Thats all I use, Mobil1 engine: Royal Purple Diffs (although, with the purple you cannot tell when the oil is dirty, because it starts out dark)

 

In the past there were problems with certain type of plastic components and were not recommended for new engines during the break-in period. I have not heard of *any* recent problems with synthetic oils, the question is usually "Do you think they are worth the price premium over petroleum products?". IMO, they are worth the price.

The problem is that some buyers try to justify the price by doubling and tripling the oil change intervals to justify the price. Synthetics do resist breakdown from heat better than petroleum products, but they still get dirty from contaminants.

 

Mobile 1 in my differentials on my cummins and jeep. Changed after 15k miles in the cummins and still looked new - clear like when i put it in. Factory stuff was black and nasty. Changed again at 32k and looked like new oil.

Changed the front differential oil on the Rubicon at 5 k to Mobile 1. The factory oil didn't look too bad. Didn't change the rear then because the dealer replaced the oil when the rear drive shaft seal and bearing was replaced (5k miles).
Changed the rear diff oil at 10k miles and it was black and nasty. Put Mobile 1 75w-140 in.

Run Mobile 1 5w-20 in the Rubicon engine. Used it for years in my previous vehicles.

Firm believer in Mobile 1!!!

 

Mobil 1 5w-20 in the engine. 75w-90 in the front diff and 75w-140 in the rear diff of my rubi.

Won't run anything else in mine. The transfer case and auto trans both use ATF+4, which if I am right, is about as synthetic as you get.

So yeah, all synthetic here.

 

Mobil 1 for me too in both diffs and the engine.

 

Mobil1 for engine.
Mobil1 ATF for transfer case.
Amsoil for differentials.

 

How exactly do you measure a 40% increase in shifting a manual transmission?