Differential Oil

[DanW]

My 2018 Wrangler JLUR has tru-lok. The front and rear axles are the Dana 44 M210 front, Dana 44 M220. The 2018 manual makes no mention of using SAE 75W-140 relative to towing. Would it be wise to use the SAE 75W-140 in my rear differential as I will likely tow a small trailer with firewood? Or should I stick to the manual and use SAE 75-85?

You can't go wrong putting 75w140 synthetic gear lube in the rear, even if you don't tow. Still, you'd probably be fine with 75w90, again, full synthetic. I've run both in mine but settled on 75w140 in the rear and 75w90 in the front, all full synthetic, since I tow a boat and utility trailer occasionally. My JK Rubi has had 75w140 its entire life and the gears are in great shape after nearly 140k miles.

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[c2m2h3]

Question:

With a New JLUR, If I went with AMSOIL Full Synthetic 75w140 in Front AND Rear, would that pose any issues ? I also plan on doing some towing....not a lot, but some.....

 

[CarbonSteel]

Question:

With a New JLUR, If I went with AMSOIL Full Synthetic 75w140 in Front AND Rear, would that pose any issues ? I also plan on doing some towing....not a lot, but some.....

No issues at all other than a potential slight MPG hit, but who buys a JLUR to use as an econobox? I have Amsoil 75W-140 in the rear and 75W-110 in the front.

 

[c2m2h3]

Why the 75W-110 in the front ?

 

[CarbonSteel]

Why the 75W-110 in the front ?

75W-110 is the upper viscosity that 75W-90 used to be before the SAE J306 tables were updated some time back. I like having a bit more viscosity protection.

 

[c2m2h3]

Got it. Thanks for the replies !

 

[jmcdtucson]

I went with Amsoil 75W90 in front and 75W140 in rear. 2oz. of Mopar friction modifier. So far, so good. No change in mileage.

 

[c2m2h3]

Are you running full synthetic ? if so, why the modifier ?

 

[jmcdtucson]

Are you running full synthetic ? if so, why the modifier ?

Sport with LSD requires a friction modifier regardless of conventional or synthetic.

 

[c2m2h3]

So a Rubi with Full Synthetic wouldn't require the modifier ?

 

[CarbonSteel]

So a Rubi with Full Synthetic wouldn't require the modifier ?

Correct; Rubicons are Electronic Locking Differentials (ELD).

 

[c2m2h3]

Thanks ! Just checking .....

 

[jeepdabest]

You can't go wrong putting 75w140 synthetic gear lube in the rear, even if you don't tow. Still, you'd probably be fine with 75w90, again, full synthetic. I've run both in mine but settled on 75w140 in the rear and 75w90 in the front, all full synthetic, since I tow a boat and utility trailer occasionally. My JK Rubi has had 75w140 its entire life and the gears are in great shape after nearly 140k miles.

Will I need to remove air dam to get to front diff?

 

[damyers8]

Will I need to remove air dam to get to front diff?

I had no issue changing out my differential fluid while the Jeep was on the ground. The front was a bit tight, but still was an easy job.

 

[jeepdabest]

I had no issue changing out my differential fluid while the Jeep was on the ground. The front was a bit tight, but still was an easy job.

Was there a particular side you approached from?

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