Differential Fluid

[rizej]

What are people using for their diff fluid when replacing the diff covers? The manual states SAE 75W85 (API GL-5) but particularly I'm interested in which brands. I see that Red Line has a 75w85 and Mobil 1 only has 75w90 so would it be better to use the Red Line gear oil...

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[JIMBOX]

I've been using VALVOLINE 75W-140 SYNTHETIC for over18 years---Synthetics diff fluids were recommended in all the JK jeeps diff. and because the RING/PINION are of the same design, I still useit-

Dana recommends it and YUKON Recommend it-
Can't beatit-

W.E.

JIMBO

 

[vavaroutsos]

What are people using for their diff fluid when replacing the diff covers? The manual states SAE 75W85 (API GL-5) but particularly I'm interested in which brands. I see that Red Line has a 75w85 and Mobil 1 only has 75w90 so would it be better to use the Red Line gear oil...

Redline usually makes top notch oils using high end Ester synthetic bases. They are a smaller company, so they don't usually spend the money to get manufacture approval on many of their products. Amsoil also makes pretty good products, and do spend the money for manufacture approval on many. I use Amsoil and some European brands (Europe seems to get better oils than the US, even from brands available in both locations) on engines that are still under warranty. For oils that don't require a manufacture approval, I often use Redline.

 

[rizej]

I've been using VALVOLINE 75W-140 SYNTHETIC for over18 years---Synthetics diff fluids were recommended in all the JK jeeps diff. and because the RING/PINION are of the same design, I still useit-

Dana recommends it and YUKON Recommend it-
Can't beatit-

W.E.

JIMBO

The higher weight would mean a higher viscosity and more resistance but is there any specific reason for choosing that over the recommended 75W-85? I'm trying to work on doing my own maintenance and mods and just wondering what would make you choose that over the other weight

 

[rizej]

Redline usually makes top notch oils using high end Ester synthetic bases. They are a smaller company, so they don't usually spend the money to get manufacture approval on many of their products. Amsoil also makes pretty good products, and do spend the money for manufacture approval on many. I use Amsoil and some European brands (Europe seems to get better oils than the US, even from brands available in both locations) on engines that are still under warranty. For oils that don't require a manufacture approval, I often use Redline.

Good to know. Do you stick with the recommended 75W-85 or something else like 75W-90 (seems to be more common)?

 

[vavaroutsos]

Good to know. Do you stick with the recommended 75W-85 or something else like 75W-90 (seems to be more common)?

I picked up some Amsoil Severe Gear 75W-90 for my diffs when I ordered motor oil from them.

 

[rizej]

I picked up some Amsoil Severe Gear 75W-90 for my diffs when I ordered motor oil from them.

Seems like the diffs will need about 4-5 quarts in total right?

 

[vavaroutsos]

Seems like the diffs will need about 4-5 quarts in total right?

The Dana 44 should take about 2 qts per axle. The Dana/Spicer nodular covers also have a raised fill plug for added capacity/high pinion angles. I don't know how much more capacity, or if it's advisable to use the high fill plug with stock pinion angles.

 

[JIMBOX]

YUP. I've had several diff. gear changes in different 4wd vehicles--Xterra/Ranger/Jeep and I've used VALVOLINE SYNTHETIC-75W-140 for all, because my gear shops(Ca/Nv) have always recommended VALVOLINE SYNTHEYTIC 75W-140 each time--especially for the BREAKIN MILES-

My '08 JKUR owners manual recommended any top SYNTHETIC 75W-140, for extended off-road/towing and polIce work

Good luck

JIMBO

 

[FrankieFJL]

YUP. I've had several diff. gear changes in different 4wd vehicles--Xterra/Ranger/Jeep and I've used VALVOLINE SYNTHETIC-75W-140 for all, because my gear shops(Ca/Nv) have always recommended VALVOLINE SYNTHEYTIC 75W-140 each time--especially for the BREAKIN MILES-

My '08 JKUR owners manual recommended any top SYNTHETIC 75W-140, for extended off-road/towing and polIce work

Good luck

JIMBO

Does the 140 mean that it is a lighter weight oil at operating temp compared to the 90 or do I have that backwards?

 

[JIMBOX]

The actual difference between the two is less than 5% and the 140 will handle the extended HIGH temps from racing/long distance towing/off-road hill/rock climbing(long time)--

The 140 will actually cause a LITTLE less in gas mileage, although it'll be pretty hard to notice--

I went to it years ago because of my speed/gear shops recommendation and the (final straw) recommendation of Chrysler in the owners manual of my '08 JKUR-I towed my off-road trailer in the SIERRAS--A LOT !

It's not recommended for use in the front diff., the majority of FORCE/WORK is still on the rear diff.--especially TOWING !

Good luck

One of my diff gear changes was the installation of YUKON 5.38 gears in my '08 JKUR--the first 20 miles at 25 miles per hour raised the temp of the rear diff. to 325 deg F and the VALVOLINE 75W-140 handled it-(recommended by the shop)

JIMBO

Does the 140 mean that it is a lighter weight oil at operating temp compared to the 90 or do I have that backwards?

 

[NovaJeep]

Sorry I'm late to the party, but I found out after I called my dealer that there is some sort of change in the 2018's diff fluid recommendations from when the manual was printed. I have a 44 LSD rear, but Mopar did in fact still recommend 75W-140 in the rear for towing and off-road use (80W-90 otherwise). I believe for the front (sport) it was 80W-90.

My manual calls for 75W-85 on both as well, so I guess it never hurts to call the dealer and check the latest recommendation for your vehicle? You would think Jeep would let us know if they changed their recommendation...

 

[JDLouisville]

Amsoil Severe Gear 100% Synthetic - 75W-90. (No tow package)
Front & Rear.

 

[JIMBOX]

I always use VALVOLINE 75W-140 SYNTHETIC for all my jeep differentials--

It was recommended for my '08 JKUR and that's what i use in my JL-

W.E.

JIMBO

 

[Crusifix]

Amsoil Severe Gear 100% Synthetic - 75W-90. (No tow package)
Front & Rear.

And it is a good thing too, as I have two cases of it from Amsoil for use in my 2015 TRDP 4runner that I traded in for the Jeep. It is fantastic that I can use what I have. This is fantastic gear oil!

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