Rear diff fluid question

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2012 Jeep Grand Cherokee / 2wd / auto 5.7 hemi. The rear diff fluid needs changing and I am getting conflicting information. Not an ELSD and manual calls for Mopar 75w-85 synthetic, which is hard to find in the stores. They sell is for $45.00 per quart.

Will Mobile 1, 75w-90 full syn with friction modifier be ok to run in rear diff?

Thanks
 
IMO, yes! The difference is too small between the two. Mobil 1's website may even have an application list for many vehicles and the site may even recommend their 75W90 LS for your JGC.
 
You can get Delo syn 75w90 from autozone around $6/qt. It does not contain LS. Works perfect in my vehicles and the price is right
 
Well, unless your GC's differential actually requires synthetic gear lube, I bought PEAK 80W90 gear oil w/limited slip additive for ~ $15/gallon at PEP BOYS. I thought this was quite a deal at their regular price. It may be a slightly higher price now.

If you can use any regular(non syn) gear oil, I'd look online for the best price.
 
75w 90 gear oil is the same stuff. Synthetic is important.
75w90 exceeds your manufacturer specifications.
People in warm climates that tow alot could even go to 75w120 synthetic oil.
Over thinking the whole thing like 5w20 v.s 5w30.
Like the difference between soda and lemonade.
 
The LSD additive in a non LSD diff won't hurt a thing. Since the manual calls for 75w90, I'd say it requires synthetic so I'd stick with it regardless.

Mobil 1, Synpower, Supertech, Delo etc. would work great here.
 
Thanks for all the responses. It does call for GL-5 synthetic...probably go with Mobile 1 or Royal Purple.
 
Originally Posted By: Lolvoguy
Agreed, Mobil 1 is far more reputable


Have used it in Eaton lockers for 20 years … I run it for 3 years/30k … but only dump it that often because it’s easy (aftermarket cover) and I cross flowing water periodically …
 
Originally Posted By: bigdawglanecreek
Thanks for all the responses. It does call for GL-5 synthetic...probably go with Mobile 1 or Royal Purple.


As much as I like Royal Purple motor oil and filters I used their gear oil in a differential once and I really didn't like it. I'd stick with Valvoline, Mobil, or generic stuff (Supertech, Masterpro, etc)
 
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Royal Purple made the diff in my GTO sound like a tin can full of rocks, it also caused the dreaded "one wheel peel" after having the diff blueprinted, rebuilt and a TurTrac added, my builder recommend Synthetic GL-5 and said Mobil 1 or any of the big name gear oils are fine, he also said Redline 75W140 NS (no FM) was some of the best out there. After shelling out $2800 bucks for a diff I decided to use Red Line 75W140 NS and 25 ml of "F" FM. I think you'll be fine with Mobil 1 but I can't recommend Royal Purple Gear oil based on my experience and my car, granted the GTO diff is a freak of nature cone type diff designed in the 60's for a freaking 6 cylinder Australian vehicle.
 
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Originally Posted By: kschachn
Definitely not Mobile 1. Use a known brand.
Originally Posted By: Lolvoguy
Agreed, Mobil 1 is far more reputable


Mixed feelings here?
 
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