Which Rear Diff fluid do I need?

[DannyPhl]

I have a 2022 Jeep Wrangler unlimited sport and I’m having trouble understanding the manual, please see the attachment.

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[grimmjeeper]

This subject gets beaten to death regularly.

The short version is:

1. Jeep recommends a thinner oil (75w85) specifically to improve fuel economy by a barely perceptible amount.
2. The axle manufacturer recommends a thicker oil (75W140) because it protects better.
3. The thinner oil will get you through the warranty period without failure.
4. After warranty, Jeep doesn't care.
5. Most people use the thicker oil.
6. Using the limited slip additive doesn't hurt anything if you don't have a limited slip.
7. Not using limited slip additive when you have one is very bad for the limited slip.

That's about it.

Just get the 75W140 and use it.

Edit: Any oil that meets API GL-5 standard is a good choice. Some other oils that haven't been tested may or may not be good. But you can't go wrong with an oil that meets spec.

2nd edit: if you have an aftermarket Eaton TrueTrac limited slip, you specifically want no limited slip additive. It works differently than the factory clutch style limited slip. The additives affect the internal gears and throw off the torque bias. It doesn't hurt anything but it reduces how much it limits slip.

 

[YJdude]

@DannyPhl does your wrangler have a limited slip rear end? Nevermind, @grimmjeeper said it all.

 

[2K6TBSS]

I just did my front and rear a few weeks ago and went with Royal Purple 75w140 in mine. I ultimately decided that I would use the viscosity that the diff manufacturer recommends. I went with Royal Purple, because I have used it for years in all my vehicles and it works well for me.

 

[Rogersocal]

Royal Purple all the way.

 

[DannyPhl]

Thanks, do you happen to know the required torque specs for the bolts on the cover?

 

[grimmjeeper]

Thanks, do you happen to know the required torque specs for the bolts on the cover?

I want to say 20 or 25 ft-lbs. It's not a lot. And you can reuse the factory gasket without RTV. Mine has been off and back on a couple of times with no leaks.

Torque specs are here: https://www.jlwranglerforums.com/complete-torque-values-for-jeep-jl-wrangler/

 

[DannyPhl]

I’m definitely overdue for a differential oil change — I’m at 55,000 miles. What got me looking into it was a noise I sometimes hear when braking. It’s not exactly a grinding noise, but it kind of sounds like the rear brakes are going bad. I had them checked and they’re fine, so hopefully changing the diff fluid clears it up… though I guess it could be something else.

 

[grimmjeeper]

I’m definitely overdue for a differential oil change — I’m at 55,000 miles. What got me looking into it was a noise I sometimes hear when braking. It’s not exactly a grinding noise, but it kind of sounds like the rear brakes are going bad. I had them checked and they’re fine, so hopefully changing the diff fluid clears it up… though I guess it could be something else.

Valvoline sells gear oil in 1 qt bags that a lot of people like to use. They make it easier to get the fluid into the differential.

I end up using pumps with hoses that I've had forever. They work great with gallon jugs.

 

[Nokones]

I would follow the factory recommendation and not the oil experts in this forum. You will need to identify which rear axle set you have in order to use the proper oil.

 

[grimmjeeper]

I would follow the factory recommendation and not the oil experts in this forum. You will need to identify which rear axle set you have in order to use the proper oil.

Even if the factory makes a recommendation based on fuel mileage rather than on longevity of the axle?

And which factory? The factory that built the axle or the factory that assembled the Jeep? They have different recommendations in this case.

 

[DannyPhl]

How many quarts would I need?

 

[Rogersocal]

3 qts total generally covers both the front and rear

 

[Dusty Dude]

Here is some Valvoline 75W-140 from Amazon. I bought this gear oil after finding this link in prior threads on this subject.

 

[sherpaJL]

@SadRobot
whatever you do, don't get this shit in your hair!

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