rear differential lube for Jeep 4x4 selec-trac

[1 FMF]

Have a 2003 Jeep grand cherokee laredo, 4x4. It has "selec-trac" on the shifter plastic. Not sure of all the drivetrain options for this vehicle, wife bought it. The owner's manual is somewhat vague. It lists both 75w-90 and Xw-140 GL-5 lube for the differentials, based on wether it's a selec-trac, or quad-trac, etc.

I rotated the tires the other day, and verified a limited-slip diff. when spinning one rear tire forward the other spun backwards. I have about 6-8 quarts of motorcraft 75w-140 syn gearlube I want to use up. I'm running this lube straight in my '02 Camaro with the torsen differential (does not require friction modifier additive) and am very happy with it. I Had been running redline 75w-90, and 80w-140, the motorcraft actually runs quieter. No more hum at highway speeds.

On the jeep, does anyone know what type differential unit they use? Do I need to go buy limited-slip additive? And if so, should I stay with motorcraft and get that brand additive, or will any do like the sta-lube additive at the parts store? Any links to Jeep info would be appreciated as well.

 

[coal68]

Perfect timing I have the same questions. I have a 94 cherokee I picked up about a year and a half ago it has 121000 miles. This is 5 speed manual 4.0l, the tranny takes 75-90, is the transfer case supposed to be filled with ATF? and do both front and rear axles take the same fluid, if so what is recomended considering I have no idea if I have the selec-trak or not.

 

[MarkC]

If you have a 5 speed, you've got Command-Trac, not SelecTrac.
75W-90 is the stuff for the rear diff, unless you tow, then you use 75W140, but I doubt it would bother anything if you don't tow.

The transfer cae does take ATF.

 

[Gary Allan]

quote:

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when spinning one rear tire forward the other spun backwards.

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Then you don't have a LS rear ..unless the clutch plates (assuming it's a TracLoc) are shot. If it was in PARK ..you may have gotten the other wheel to turn in the opposite direction with decent amount of force on the lug wrench ..but if it turned freely ..it's open.

I'm uncertain what diff you have. You may have a D35 ..or if you're lucky, a D44.

 

[coal68]

So would I be safe running the 75-90 throughout the tranny and both axles. with dexron II in the transfer case?
Thnks for the help.

 

[Greaser]

quote:

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Originally posted by 1 FMF:
Have a 2003 Jeep grand cherokee laredo, 4x4. It has "selec-trac" on the shifter plastic. Not sure of all the drivetrain options for this vehicle, wife bought it. The owner's manual is somewhat vague. It lists both 75w-90 and Xw-140 GL-5 lube for the differentials, based on wether it's a selec-trac, or quad-trac, etc.

I rotated the tires the other day, and verified a limited-slip diff. when spinning one rear tire forward the other spun backwards. I have about 6-8 quarts of motorcraft 75w-140 syn gearlube I want to use up. I'm running this lube straight in my '02 Camaro with the torsen differential (does not require friction modifier additive) and am very happy with it. I Had been running redline 75w-90, and 80w-140, the motorcraft actually runs quieter. No more hum at highway speeds.

On the jeep, does anyone know what type differential unit they use? Do I need to go buy limited-slip additive? And if so, should I stay with motorcraft and get that brand additive, or will any do like the sta-lube additive at the parts store? Any links to Jeep info would be appreciated as well.

---

http://www.jeepin.com/

 

[Brett Miller]

I used Amsoil Severe Gear 75W-90 in my wife's 2001

 

[TheTanSedan]

We run REDLINE in out 2WD '01 XJ.

Recommend you also check the forums on http://www.jeepsunlimited.com/

 

[coal68]

Will it damage any thing if I put a friction modifier in a rearend that does not need it.

 

[1 FMF]

followup:
I wish Chrysler would either call it an open diff. or limited-slip. After research and figuring out chrysler's vocabulary for things, I have an open rear differential. Also became apparent when I pulled the rear diff. cover off, but the purpose was to know before doing the work. It's actually a Dana/Spicer 35C, iron housing. Worst thing was I went to parts store to get the cover gasket, and their freaking computer has all models listed as having the Dana 44M, which is an aluminum housing and according to Jeep specific websites is only on late models with the V-8. So in the middle of the job I had to run back to the store, which I was trying to avoid in the first place, and get the correct gasket. What did the auto parts industry ever do before computers and electronic inventory parts lists ?

After 5 minutes of me watch the guy punch computer keys, and me continuously ask, "you can't just get me the gasket for a dana 35c?", he finally found the 1997 Jeep Cherokee 4.0L listed as having a Dana 35C and then knew which felpro gasket to grab off the shelf. He had doubts too, and believed his computer was right and I was not, but I was smart enough to bring the diff. cover with me and the gasket matched perfect. Of course he didn't know what to say, especially when I asked if he thinks their computer system is correct.

I also have a 42RE transmission. It is a Selec-Trac, not the Quad-Trac. Chrysler's word for the limited slip differentials is Vari-lok, which I don't have. Both differentials are simple open diffs.

What was also interesting was the tag on the rear diff cover, it said "75W-140SYN". Also have 3.55 gears, as marked on the ring gear.
In went the Motorcraft 75w-140, no additive used, Jeep has 100 miles on it since, all is great.

No, adding friction modifier or limited-slip additive as it's also called won't hurt anything. Purpose of it is only to allow the clutch plates in a limited-slip differential to slip smoothly and not chatter, when one wheel spins at a different speed from turning. Adding it to an open differential is only wasting it, and money; I did not want to have to buy any.
Also, the recommended max amount of friction modifier to use is something like 4 ounces per 2 quarts, more than that and gear life might suffer, or so i've read.

I was also wrong about the wheels spinning opposite directions meaning it's a limited slip

However the torsen differential will do that and it is a limited-slip, by design different (no frictional clutches), maybe that's why I was thinking that.

 

[coal68]

You rock! Thats about it and the info on jeep rear ends is back asswards.

 

[47HO]

BTW, Jeep offers two diferent "limited slip" diffs, one is called Trac-Lock and the other Vari-Lock. They are different.

 

[MolaKule]

check out:

http://www.specialtyformulations.com/index_files/Page1458.htm

Coal68,

The only thing you would hurt is your pocket book.

 

[1maniac]

Yeah, Jeeps are funny. I couldn't find a straight answer to my '04 Wrangler at first. It's always "if this then this or that then that unless this and that are not available then you can use that or this if you have the "A" system unless it was made after this date then you must consult the service manual."

Anyway I bow run Amsoil 75w90 front and rear with no problems.

To be honest my BMW is the same way; no straight answer.

 

[Greaser]

I've been using Pennzoil synthetic gear lube on four Jeeps I service with no complaints.