19Delta

Going to be looking at my stock broke locker this afternoon and need to stop and grab some fluid. I have a aftermarket diff cover, so I can't use the fill hole as a full guide. I read 1.35, and I read 2 quarts. Which is it? What is the weight? I have read 75W90, and I have heard much thicker.


Thanks!

tslewisz

Here you go:

Project-JK.com - Jeep JK Wrangler Resource » Jeep JK Wrangler Maintenance Differential Fluid Change Write-Up

Higher vis lubes are for the rear when using the rig for towing.

JeepersLife

I talked to my dealership about my '11 Rubi Ulim and they said 2qts front & rear. I also asked them about they weight, I told them I know the book calls for 75W90 or 80, but what do you put in when you do diff oil changes? They said 75W140 (which it calls for, for towing applications & etc.). So I clarified and said if I change mine and put 75W140 I'm good to go? Answer yes.

So, I got 4qts Royal Purple 75W140 which also has a friction modifier in it. Since they tried to sell me 4 8oz Friction Modifier additives at $10 something each. I also called RP and asked them about the friction modifier additive in their oil (because of the whole limited slip and electronic lockers) and they said I should be good to go, however if I hear any grinding and what-not, I would have to add some more friction additive (which dealership was trying to sell me)

Hope this helps...

4x4chick

The owners manuel say to use 75W140 synthetic oil in the diff if you are going to tow a trailer. I asked my local Jeep dealer and they said that all the use in all the Jeeps are the 75W140. We live down in the desert where it is hot!!!

I just change my diff covers 2 weeks ago with the Poison Spider ones and had a hard time finding out how much oil to put in. Called Poison Spider and the said 1.35 quarts front and back for the D44 with e-lockers. The dealer said 2 to 3 quarts for is so I was clueless.

Decided to measure the oil when I drained it and it was exactly 2 quarts front and back, so i just replaced it with 2 quarts front and back and all seems to be well.

Hope this help you.

Gort

Interesting -- I was under the impression that the Unlimited Rubi, or at least my 12 anyway, had open diffs with the lockers (relying on the BLD when the lockers aren't engaged). My wife has an 11 Sport S and her window sticker shows "Trac-Lok Limited Slip Rear Differential" but my window sticker shows no such option. Was LS an an option with the lockers or is it just assumed on the Rubis?

I'd be grateful if someone could clarify this because I was planning on changing the fluid in my diffs and transfer case this weekend and I want to make sure I get additive if I need it.

rinkishJK

Rubicon axles with the locker do not need limited slip additive.. Its only for limited slip axles.
Putting a limited slip fluid in the rubi won't affect anything. Most good fluids like rp have the friction modifier already in it.
I run amsoil in my rubi axles
Also 75w140 is only recommend for the rear axle for towing. Not the front.

Gort

Excellent -- that's what I thought.

I was also wondering about the front axle -- even though the OM only recommends the heavier stuff for the rear when towing, is there any harm in running the 75W-140 in the front, too?

I do have a trailer that I tow. The main reason I was going to change out the fluid in the diffs was to ensure that I had the 75W-140 (good synthetic) in there. The transfer case was just because.

19Delta

Thanks for all replies! Do they make something in the middle? Like 75W110 or ???

rinkishJK

No. 75w140 and 75W 90 are synthetic lubes.. 80W 90 is not. There is no 75W 110.
Another key point is the viscosity numbers.
So the first number is the cold viscosity, and the second the hot viscosity, which is why and old school trick for startup tick and oil burning is to just use 15w40, instead of 10w30.

Gort

I noticed the lack of 80W-90 synthetic when I was searching around the local auto parts places.

Do you think it'd be fine to run the 75W-90 in the front diff instead of the 80W-90 it calls for? Would it be OK to put the 75W-140 synthetic in both the front and the rear instead of just the rear?