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Strawman
01-01-2016, 10:38 PM
Noob question of the day (although it was debated on another site for a while)


On a JKU Rubicon does the rear differential require limited slip additive?



Also for the most part are people running the 80w90 or the 75w140?

Peak
01-02-2016, 01:20 AM
The manual recommends 75w-90, that's what I run as well as many people on this forum. As for the limited slip additive, I'm not to sure since I don't own a rubi. I'm sure another member will chime in on that.

wayoflife
01-02-2016, 01:32 AM
You do NOT need to use friction modifier in a rubicon axle. That being said, pretty much all synthetic gear oil has it in it and if that's what you're using, it really doesn't matter.

As far as weight goes, I would use what is recommended in the manual unless you're running 5.13 gears or higher. At that ratio, I might consider a heavier weight fluid.

Ddays
01-02-2016, 02:15 AM
You do NOT need to use friction modifier in a rubicon axle. That being said, pretty much all synthetic gear oil has it in it and if that's what you're using, it really doesn't matter.

As far as weight goes, I would use what is recommended in the manual unless you're running 5.13 gears or higher. At that ratio, I might consider a heavier weight fluid.

I've never heard that tip before (heavier oil with 5:13 or higher) - why is that?

ScoobyCarolanNC
01-02-2016, 02:45 AM
I've never heard that tip before (heavier oil with 5:13 or higher) - why is that?

Once the mechanics of the diff change so do the oil's requirements. Oil primarily does 2 things, lubricate & dissipate heat. As it gets hotter oil gets thinner & doesn't lubricate as well. The gear manufacturer should tell you what to run and how much once you upgrade.

jeeeep
01-02-2016, 05:52 AM
manual recommends the heavier weight oil when towing (load). with all the add-ons and off-road use, I figure that's reason enough to use the heavier recommended oil to try and keep things as cool as possible.

Ddays
01-02-2016, 12:37 PM
Once the mechanics of the diff change so do the oil's requirements. Oil primarily does 2 things, lubricate & dissipate heat. As it gets hotter oil gets thinner & doesn't lubricate as well. The gear manufacturer should tell you what to run and how much once you upgrade.


manual recommends the heavier weight oil when towing (load). with all the add-ons and off-road use, I figure that's reason enough to use the heavier recommended oil to try and keep things as cool as possible.

Gotcha, that all makes sense, I just never heard to go heavier because of a ratio change before....