Rear differential fluid change

[Ashley.ennis27]

Hello, I have a 2018 Sport 3.6 with 100,000 miles on it. I need to do a read diff fluid change. I’m getting mixed answers as to what fluid to use. My manual says 75W85. Everything I’m reading on here and Facebook is saying 75W140. I’m unclear which one to use and how much.

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[garyji]

Is this the first time???? 100K??

A quick google search came up with this: The 2018 Jeep Wrangler JL rear differential (M220/Dana 44) requires approximately 1.22 to 1.53 quarts (1.15 - 1.45 liters) of fluid. For most applications, a 75W-85 or 75W-90 GL-5 gear oil is recommended, though 75W-140 is often used for towing.

Can't hurt to use the 75/140.

G.

 

[Ashley.ennis27]

Can I use the same for both front and rear?

 

[BUSHRVN]

If you’re not towing or running large tires, 75W85 is fine. Heavier oil like 75W90 or 75W140 in the rear won’t hurt anything, maybe an unnoticeable, unmeasurable fuel economy hit. I personally run 75W140 in the rear and 75W90 in the front. I occasionally tow a 2,500lb boat in the summer with it. Mines a Diesel.

 

[BUSHRVN]

Definitely use the bagged fluids like Valvoline as Gary showed, it’s the only sane way to go and that’s the brand I use too.
Using heavier oil in the front won’t hurt anything but is far from needed.

 

[Traveller128]

75W85 is an oil for EPA fuel economy, 75W90 is a good all around oil. If you run large tires or tow the 75W140 is the better choice. GL-5 is the rating you're looking for.

If you have a limited slip don't forget the additive.

 

[Traveller128]

Can I use the same for both front and rear?

Sport will have the M186 Super 30 front, good oil for that is 75W90. If you are pretty stock, I'd use it in the rear also (D35 or D44). 75W140 is for a bit more shear strength ability for a little higher load protection.

 

[zouch]

that should say "If you have a CLUTCH PACK STYLE limited slip don't forget the additive."
gear-driven limited slips want NO additive.

admittedly this is probably moot in this case since if the OP hasn't changed fluid in 100K miles they most likely did not upgrade to a gear-driven limited slip.

75W85 is an oil for EPA fuel economy, 75W90 is a good all around oil. If you run large tires or tow the 75W140 is the better choice. GL-5 is the rating you're looking for.

If you have a limited slip don't forget the additive.

 

[Traveller128]

that should say "If you have a CLUTCH PACK STYLE limited slip don't forget the additive."
gear-driven limited slips want NO additive.

admittedly this is probably moot in this case since if the OP hasn't changed fluid in 100K miles they most likely did not upgrade to a gear-driven limited slip.

2018 Sport either has an open diff or a clutch type (optional) M220. If they don't know which oil to replace with, I'm doubting someone changed the diff. Just playing the odds in saying don't forget the additive if it has the optional limited slip.

 

[Rebel Scum 68]

75W85 is an oil for EPA fuel economy, 75W90 is a good all around oil. If you run large tires or tow the 75W140 is the better choice. GL-5 is the rating you're looking for.

If you have a limited slip don't forget the additive.

If using the Valvoline 75w-140 mentioned above, what's a good additive? Any recommendations other than the Mopar stuff?

EDIT: I see the Valvoline comes with Limited Slip Additive.

 

[zouch]

agreed with the specs and the assumptions.

just didn't want anyone reading your statement and thinking it was all-inclusive.

2018 Sport either has an open diff or a clutch type (optional) M220. If they don't know which oil to replace with, I'm doubting someone changed the diff. Just playing the odds in saying don't forget the additive if it has the optional limited slip.

 

[SCJeeps]

I would recommend using a high quality synthetic gear oil that meets GL-5; Mobil 1, etc. While I think you can run either recommended viscosity it should be noted that running the heavier 140 does come with some potential trade off cost. While on paper the 140 has a higher viscosity and will protect more it will also operate at a higher temperature versus the 90. In a previous life I did testing on the JL pinion bearings( bearing test rig) working to certify the 140 weight oils, that test generated a higher sump temperature due to oil viscosity alone( bearing and load was the same). All that said again my strongest recommendation is to use high quality gear oil and change the fluids more often. This generation Dana rear end has lost oil volume compared to previous, which reduces heat shedding ability. I know when I changed my diff fluid at 20k some miles it was fairly dirty which was surprising to me, so I will be doing it more often.

 

[Capt. Don]

Dana Spicer, the manufacturer of our axles, recommends 75W-140 synthetic in the M210 / M220 Dana 44 Advan-Tek axles. I have run originally the factory 75W-90 synthetic and now the Valvoline 75W-140 synthetic and have found the heavier weight oil really quieted and smoothed out the gear and clutch action on the M220 wide rear axle at low speed. It was a noticeable difference with 4.56 gears. Probably less with 3.70 gears or lower numerically. For the front axle in your Sport I would think that the 75W-90 synthetic is a good recommendation but you might want to check with Dana Spicer. They know their axles and what it takes to make them last. Jeep is pulled by many different considerations besides performance and durability.

 

[Megawatt]

Just changed my rear diff oil last week. 44k miles and it looked surprisingly good. I drive 70 miles a day on the highway for work and never tow anything on my lifted rig.

Dealership wanted $75 a quart for the mopar stuff. I did the valvoline bag and not the 140 weight stuff.

 

[zouch]

can you share the source for where you found the specs you're quoting here?
i've poked around a bit and found conflicting info, and nothing unmistakable that's from Dana.

what i see paraphrased most often is something lighter in the front.

Dana Spicer, the manufacturer of our axles, recommends 75W-140 synthetic in the M210 / M220 Dana 44 Advan-Tek axles. I have run originally the factory 75W-90 synthetic and now the Valvoline 75W-140 synthetic and have found the heavier weight oil really quieted and smoothed out the gear and clutch action on the M220 wide rear axle at low speed. It was a noticeable difference with 4.56 gears. Probably less with 3.70 gears or lower numerically. For the front axle in your Sport I would think that the 75W-90 synthetic is a good recommendation but you might want to check with Dana Spicer. They know their axles and what it takes to make them last. Jeep is pulled by many different considerations besides performance and durability.

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