bigblue91601

Good afternoon to all, I probably have a silly question, but hope somebody can answer my question. I have a 93 grand Cherokee with the 5.2, I have the Dana 30 and Dana 35 axles. I’m going to be doing my very first diff fluid change in it, but have come across some different information as to which fluid to use. I’ve seen some people say to use 80w-90 and others say 75w-140. I’m pretty sure I don’t have the LSD and as far as towing, I have towed with it, but only a couple times, and if I do tow, it’s pretty light stuff. So hoping you guys can tell me which fluid to run please

dave1123

If your climate is generally above 70*F most of the time, use 80w-90. I you live in areas where it gets well below freezing 1/2 the year, use 75w-140, but remember that's a synthetic designed for low temperatures.

00t444e

I run 85w140 in all my axles.

bigblue91601

I live in an area that has a little bit of everything as far as weather goes, I think the coldest it’s gotten in recent years was 15-20 degrees above 0, and usually I’d say it’s about 60-70 degrees when it’s not winter or summer

dave1123

My opinion is 80w-90 is good unless it gets below zero a lot. Even then the diffs will warm up soon enough not to cause any problems.

bigblue91601

Thanks! I’ll go with that

bigblue91601

so I called my dealership and asked them to give me some more details on the axles that I have and I found out I have LSD in mine and they were telling me to use 75w-140 but I’ve already poured the 80w-90, am I still fine with the 80 or should I start over with the 75?

dave1123

You'll have to add a friction modifier so the clutch plates in the LSD don't slip or not engage. The 75w-140 has some of that in it, but still needs a bit more. To be safe, you should probably drain it by taking the cover off and checking to see if you really do have a limited slip. It would have been nice to know that before I gave you advise.

wingless

The '94 FSM has lubricants specified for three temperature ranges: above 90°F; -10°F to 90°F and below -10°F.

All vehicles were filled at the factory w/ SAE 80W-90 lubricant. Vehicles w/ rear anti slip also have the friction modifier added.

For the -10°F to 90°F range the specified lubricants are: SAE 90; SAE 80W-90; SAE 80W-140 and SAE 85W-140.

The FSM specifies that periodic change is not required and specifies that fluid should be changed if contaminated.

bigblue91601

bigblue91601

Thanks guys! I wish I would’ve also known but I know now and I appreciate all of your guys is feedback, got some friction modifier today at Jeep dealership, hey here’s a weird one when I was cleaning the outside of my diff cover, it has a date stamped on it was like 9-25-91 but my Jeep is a 93, so why the 91?

dave1123

It may have been warehoused that long or been replaced at one time. That is date of manufacture, not date of installation.

That doesn't look like an LSD to me.

00t444e

80w90 will be fine, don't worry about the friction modifier, the clutches are likely so worn out that it won't make a difference.

bigblue91601

Dave, what makes you believe that it doesn’t have an LSD? I honestly dont know the difference Just by looking, is it true that if I raise the rear end and spin one tire, the other should spin in the same direction? And that’s a good indicator if I have an lsd or not?

wingless

The axle was built w/ a tag having embossed text that identifies the axle, retained by cover bolts.

The limited slip rear axle was also built w/ a tag identifying that version.