I currently have a 2010 Rubicon. Is there any specific Diff fluid recommended or does everyone run Mopar oil?!?

 

I run royal purple, honestly I wont be doing it again purely for price reasons. I will probably run lucas or mobile 1

 

Is it just 80/90 weight and does it have to have a special blend or additive in it

 

I used Mobile 1...

Followed the steps shown in this writeup


http://project-jk.com/jeep-jk-write-...hange-write-up

 

I use Mobil 1 also, 75w90 weight. The above post does give good "how to" instructions.

The Rubi has an E locker and it requires no special additives, some limited slip type differentials might, but not your Rubicon.

 

Well I just threw on ARB covers on '10 Rubi and put in Royal Purple. Just follow that thread on how to do, really easy. I am a believer in you get what you pay for.

 

Royal Purple 75/90. Best stuff out there in my opinion.

 

Same here.

 

I had a friend who's camaro was on Horsepower TV. He had mobile 1 in the engine and rear diff. The show dynoed the car, then changed the engine, trans and diff over to royal purple. When they dynoed again they picked up 8 hp at the wheels. I've been sold on it since for diffs and transmissions.

 

Were they comparing old fluids of one brand to fresh fluids of another? That's not good science. Correlation does not imply causation.

If they put in all new fluids (Brand X), did the dyno and then replaced the fluids with new Brand Y and repeated the dyno, that would give data worth considering.

Otherwise it is just old fluid vs new fluids. With the tranny likely the biggest influence. A still better test would be to change only one variable at a time.
And, of course, repeat!