What 80w-90 front diff gear oil are you using??

[Chomper]

Seems like 80w-90 is not one of the more available grades regarding selection.

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[Litfuse]

I’ll use 75w-90 Amsoil.

 

[SecondTJ]

Valvoline 80w90

 

[plex]

Seems like 80w-90 is not one of the more available grades regarding selection.

Royal Purple 75w90 will be fine for your front, also with FAD unless you did a lot of 4WD, there is really no need for front diff fluid change under 50k miles.

 

[SecondTJ]

also with FAD unless you did a lot of 4WD, there is really no need for front diff fluid change under 50k miles.

Keep in mind that even with FAD, everything in the front axle is still turning when you drive. (only exception is the R&P)

 

[allenn]

75-90

 

[Chomper]

Is there a real difference between 75w-90 and 80w-90?

The updated specs for the JL call for 80w-90. I don't want any potential warranty issues for using out of spec gear oil.

 

[SecondTJ]

Is there a real difference between 75w-90 and 80w-90?

The updated specs for the JL call for 80w-90. I don't want any potential warranty issues for using out of spec gear oil.

Wrangler has had 80w90 spec for decades. Lots of people have used 75w90 without ill effect

 

[Chomper]

Wrangler has had 80w90 spec for decades. Lots of people have used 75w90 without ill effect

My owners manual says differently, though I understand the spec has been updated to 80w90.

Axle Differential (Front) We recommend you use Mopar Gear & Axle Lubricant
(SAE 75W85)(API GL-5)
Axle Differential (Rear) We recommend you use Mopar Gear & Axle Lubricant
(SAE 75W85)(API GL-5). Models equipped with Trac-Lok
Limited Slip Differential require a friction modifier addi-
tive.

 

[Redneck_Jedi]

From my 2019 Owners Manual...

Axle Differential (Front Axles)
We recommend you use Mopar Gear & Axle Lubricant (SAE75W85)(API GL-5)

Axle Differential (Rear M200 Sales Code DRZ)
We recommend you use Mopar Gear & Axle Lubricant (SAE75W140)(API GL-5).

Axle Differential (Rear M220 Sales Codes DRE/DRF)
We recommend you use Mopar Gear & Axle Lubricant (SAE75W85)(API GL-5).
Models equipped with Trac-Lok Limited Slip Differential require a friction modifier additive.


Anyone know why Jeep doesn't recommend changing the gear oil at the first oil change? I know when you have new gears installed, they always recommend changing it within 500 to 1k miles because of gear break-in and the possibility or metal shavings.

 

[VNT]

I just changed mine, rear D44 with LSD, used some Redline 75W-140 and for the front Amsoil Severe Gear 75W-90. had 7300 miles and rear fluid was dark with lots of paste on the magnet, front not as bad. Glad I changed it. Also did the Selec Trac T-case, used Amsoil SS ATF. Should be good to go for a while.

 

[Bearded_Dragon]

I just changed mine, rear D44 with LSD, used some Redline 75W-140 and for the front Amsoil Severe Gear 75W-90. had 7300 miles and rear fluid was dark with lots of paste on the magnet, front not as bad. Glad I changed it. Also did the Selec Trac T-case, used Amsoil SS ATF. Should be good to go for a while.

How many miles did the transfer case fluid have, and how did it look?

 

[VNT]

7300, looked darker,hard to tell condition without an analysis, but 10 minutes work and 2 qts of fluid, better to change it and flush out the break in metals. no magnets on the plug in the t-case.

 

[ChattVol]

Is there a real difference between 75w-90 and 80w-90?

The updated specs for the JL call for 80w-90. I don't want any potential warranty issues for using out of spec gear oil.

I just did a diff cover change and called Dana...they said 75w90 was fine to use for the jl rubi axles.

 

[DanW]

How many miles did the transfer case fluid have, and how did it look?

I changed mine at 16k and it looked perfect. T-case fluid is ATF+4. Chrysler transmissions typically recommend 100k changes for auto trannys using ATF+4. The transfer case gets MUCH less wear and tear than a transmission. So why did I do it? It was cheap, I like getting break-in crap out, and I was heading to Moab soon after. It just made me feel better. I used NAPA ATF+4 which is very cheap and made by Valvoline.

As for diffs, synthetic 75w90 has 80w90 completely covered. There is no issue in substituting it. It will out perform 80w90 at every temperature. The viscosity difference would be barely noticeable in a lab, and probably completely unnoticeable to the naked eye or the touch, except at 30 below zero, where the 80w90 would flow like chewing gum.

As said before, the front diff gets barely any wear because most of the time it has no working load on it. The axles turning cause next to no stress. Either the 75 or 80 GL5 will make it outlast the rest of the Jeep if you keep it topped off.

Change it early to feel good, or change it by the book and you can still feel good. For me, I'll change it more often because I like to tinker with my Jeep.

I've currently got Valvoline synthetic in both ends, with 75w140 in the rear. I changed it, too, at 16k and the fluid looked good, but had plenty of wear metal on the magnet. I did have 75w90 in the rear for the trip to Moab. I had it laying around. I swapped it to the 140 when I returned home. The 140 is recommended for towing, which I do, but didn't do on that trip. There was very little wear metal on the magnet after the trip. Almost none. I only ran a few thousand miles on it.

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