Diff fluid - Wrangler JL

[infidel1911]

Hi all,

What diff oil weight would you recommend for a 2 door JL sport that is mainly highway driven in Arizona? Jeep doesn't go offroad at all, no towing. My daughter just uses it to commmute. Thanks

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[Old Dogger]

Hi all,

What diff oil weight would you recommend for a 2 door JL sport that is mainly highway driven in Arizona? Jeep doesn't go offroad at all, no towing. My daughter just uses it to commmute. Thanks

The recommended if not towing, is 80W90 Synthetic gear lube. I am also in AZ. I run Lucas 75W90 in mine. Very similar.

 

[infidel1911]

Do you run 75W90 in the rear diff as well?

 

[sdebol]

Other than slightly worse gas mileage (how much of a hit do you get?) is there any other negative to using 75w-140 in the front? (This is for a Sahara, not Rubicon). I usually use the 75w-140 in the rear but it would be easier to just buy one type all the time...

 

[wolf]

75W140 front and rear on my jlr. Dana 44 recommended. Remember heat. Been using for years. Fluids are the life blood of a vehicle. I also use Amsoil 0W20 in my 3.6. I change my oil and differential fluid at 5000 miles as well as rotate the tires. I know it’s not necessary to do that often but I don’t care. Works for me. ?

 

[Erievon]

Sports and Saharas have the D30 front and D35 rear. Is 140 overkill for those, or maybe even more important to have 140 since they're smaller? Thoughts?

 

[roaniecowpony]

Just thinking back with older vehicles I've had. One car had close to 500,000 miles on the original rear end (all components) and it had 90w "hypoid gear oil" in it for its whole life when I sold the car working fine. That gear oil was mineral oil, not the high performance synthetics of today, and the engines in that car much higher torque/hp, the ring gear was smaller as well.

 

[grimmjeeper]

I've never seen or ever heard about a heat related failure using 75W90 even in an abused Jeep. So that's what I run.

I change it out on the recommended schedule or if it gets contaminated, whichever comes first. Also, I've opened up the diffs a few times for other things so it gets new fluid when I do that.

You can go with 75W140 if you feel like it. But I don't see any measurable difference in real world daily use that makes me want to run that.

 

[Old Dogger]

Do you run 75W90 in the rear diff as well?

Yes…non issue, as long as not towing. I had this on my self, because I also run it in my JKR. But the recommended is 80W90.

 

[QwikKotaTx]

Wife has a Sahara with a manual and 3.6L and limited slip. The rear looks to be the Dana 44 but not sure about the front? Also, is there a limited slip up front?

ETA: build sheet says M186, I believe that is the Dana 30 front.

 

[AMT]

75W-110 in the front (50/50 mix of 75W-90 and 75W-140)

75W-140 in the rear

Just did mine for the first time. Same as above

Bought 2 qts. of 140 and 1 qt. of 90 (Royal Purple). Filled the rear diff. until full with 140 (~1.6 qts.).
Used the whole qt. of 90 in the front and filled the rest of the way with 140. This was recommended a few times in other threads and I followed suit.

 

[wolf]

Just thinking back with older vehicles I've had. One car had close to 500,000 miles on the original rear end (all components) and it had 90w "hypoid gear oil" in it for its whole life when I sold the car working fine. That gear oil was mineral oil, not the high performance synthetics of today, and the engines in that car much higher torque/hp, the ring gear was smaller as well.

Funny you mention mineral oil. My 0235 Lycoming came with mineral oil as the break in oil. Then per instructions switched to the regular oil at first oil change I think it was 25 hrs.

 

[mushroomax]

You can't even get 2qts in them thingemebobers so why not run a heavier weight like 75W140 to help with all that heat?
I keep a gallon of 75W140 synthetic on the shelf for front and rear fills --> JLUR

 

[roaniecowpony]

You can't even get 2qts in them thingemebobers so why not run a heavier weight like 75W140 to help with all that heat?
I keep a gallon of 75W140 synthetic on the shelf for front and rear fills --> JLUR

Do we know how hot these things are running? They seem to be sized like most other vehicles. I recall running oil coolers on road race car diffs way back. Are we having temps needing a cooler?

 

[CarbonSteel]

Just thinking back with older vehicles I've had. One car had close to 500,000 miles on the original rear end (all components) and it had 90w "hypoid gear oil" in it for its whole life when I sold the car working fine. That gear oil was mineral oil, not the high performance synthetics of today, and the engines in that car much higher torque/hp, the ring gear was smaller as well.

Yep; I have had a few like that too--but they were not "hamstrung" as FCA has done. They all held at least 2.5-3QTs of oil and that makes a big difference.

In addition:

-- FCA reduced the oil capacity in the JL rear axles vs. JK (Dana 44):
-- JL rear = 1.4-1.6Qts; JK rear = 2.3QTs; reducing the capacity also reduces oil life and protection capability.
-- Advantek axles run hotter than previous generations and hotter than comparable axles by competitors; higher oil temperatures equals less protection and lower oil life.
-- API revised the J306 tables in 2005 and added 75W-110 as a viscosity. This is important because the viscosity range for xxW-90 used to be between 13.5 and 24.0 cSt @ 100°C. It is now between 13.5 and 18.5 cSt @100°C. Therefore, xW-90 gear oil prior to 2005 was 27% more viscous which also equates to additional protection against wear.

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