I am a new owner of a 92 XJ with 175k miles. This weekend I want to change out the differential fluid and am looking for what weight and type of gear oil to use. I plan on towing a tent trailer and noticed that the Haynes manual recommends a synthetic oil for the rear diff. The dealer recommeded an additive by I forgot to ask what type. Any tips or recommedations on oils and where to purchase them in the Los Angeles/Orange County area?
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
Differential Fluid
- Thread starter karstic
- Start date
WI88XJ
NAXJA Forum User
- Location
- South Central Wisconsin
If the dealer recomended an additive then you've got a limited slip diff. I would just go and buy your fluid and the additive from the dealer. There seems to be a difference between company's additives and I believe the concenses around here is to get this from the dealer.
I run a locker in the rear and I'm using Mobil 1 synthetic.
I run a locker in the rear and I'm using Mobil 1 synthetic.
Runnin'OnEmpty
NAXJA Forum User
- Location
- Southeast USA
Karstic, since you're towing, I would use a 80W-140 weight synthetic gear oil rated GL-5. WI88XJ's Mobil 1 is a good one.
Most synthetics do not require a limited slip additive. It will say on the bottle if an additive is required.
You can find gear lubes at any auto parts store.
Most synthetics do not require a limited slip additive. It will say on the bottle if an additive is required.
You can find gear lubes at any auto parts store.
Is there a problem if you use synthetic oil after having regular oil in the differential? I called a local dealership to see what they recommend and I mentioned using synthetic oil in the rear diff but the guy on the phone advised against it. Whats the scoop?
Runnin'OnEmpty
NAXJA Forum User
- Location
- Southeast USA
You can switch from type to type with no problems. Both the synthetic and mineral oil types are compatable with each other. In fact, you can even buy "blends" which are mixtures of both.
If you are towing, the synthetic oil is a good choice. It stands up to the higher temps generated from towing, better than mineral oil does.
Make sure it is API rated GL-5, though. This rating has more extreme pressure additives in the oil, and is what you want to run in differentials (as opposed to the GL-4's).
I don't know why the dealer guy didn't recommend the synthetic. Different people have different opinions on oils. If you don't have confidence in using synthetic, just use a GL-5 rated mineral oil, in 80W-140 weight. It will do fine, but you may need to change it more often.
If you are towing, the synthetic oil is a good choice. It stands up to the higher temps generated from towing, better than mineral oil does.
Make sure it is API rated GL-5, though. This rating has more extreme pressure additives in the oil, and is what you want to run in differentials (as opposed to the GL-4's).
I don't know why the dealer guy didn't recommend the synthetic. Different people have different opinions on oils. If you don't have confidence in using synthetic, just use a GL-5 rated mineral oil, in 80W-140 weight. It will do fine, but you may need to change it more often.
- Location
- Terra Firma
The factory recommends synthetic lube in differentials when used for towing. Ignore the idiot at the dealership. I asked the manager of my dealership's quick lube operation about using synthetic oil once. He told me I shouldn't use it "because synthetic oil runs at a higher pressure and on the highway that increased oil pressure will blow all the seals out of your engine."
Yeah, right. I've been running synthetic for over 50,000 miles now (starting at 175,000) and haven't blown the seals out yet.
Yeah, right. I've been running synthetic for over 50,000 miles now (starting at 175,000) and haven't blown the seals out yet.
- Location
- Westminster, SoCal
Umm.... good luck finding an 85 140 synth someplace around town.... I have driven everywhere and finally when I found it at NAPA it was about $40 for 2 qts!!!! So I went with VAlvoline synth mix.
In regards to the friction modifier... don't use the aftermarket ones, just go with the dealer one...
Kejtar
P.S. WHere in LA OC are you? Visit the SoCal Chapter Forum
In regards to the friction modifier... don't use the aftermarket ones, just go with the dealer one...
Kejtar
P.S. WHere in LA OC are you? Visit the SoCal Chapter Forum
- Location
- Westminster, SoCal
Cool.... if you even need some help give me a holler.... Time permitting I can stop by 
With the amount of miles I put on my XJ, I think I am a specialist when it comes to changing the diff fluid LOL
Another thing that people don't think about sometimes is that damn rubber plug (if that's what you have). After 5 years I finaly replaced mine as it got so hard it was damn near impossible to take it out without getting it into pieces..... I think it was about $2 from the dealer.
Kejtar
With the amount of miles I put on my XJ, I think I am a specialist when it comes to changing the diff fluid LOLAnother thing that people don't think about sometimes is that damn rubber plug (if that's what you have). After 5 years I finaly replaced mine as it got so hard it was damn near impossible to take it out without getting it into pieces..... I think it was about $2 from the dealer.
Kejtar
