Front and Rear Diff Fluid?
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
My 02 had two different fluid requirements. I think it was 75w110 for the front and 75w140 for the rear, I know it was sightly different. I put Royal Purple in mine, it had a good additive for the stock LS so no chatter.
Posting Guru
Joined: Jan 2009
Posts: 1,321
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From: Mattawa Washington.
Royal purple is full synthetic, good choice. If you want to keep the heat down full synthetic is a must. Axles never get serviced enough or monitered for the heat. Play it safe and spend the extra money.You will get a longer bearing life.... ei. years ago baught a new potato digger the main gear box kept getting so hot the paint would burn and the seals would melt literally... Dealer put 3 new gear boxes on same problem and this was happening to all the new diggers they had sold!!! Factory took a long shot and told them to dump the standard gear oil and put in synthetic, gearbox ran warm too the touch but that was it after installing synthetic. We use synthetic in all our gear applications now. Sorry for the long post.
Cargo Master
Joined: Apr 2006
Posts: 3,215
Likes: 7
From: WV
Another option for fully synthetic is Red Line. I've used it for years in my Ranger, Mustang, and Explorer without problems so I put it in my SD. It also has the friction modifier in it. Bought it from Summit Racing.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
I will say this:
I used Royal Purple 75W140 when I changed out my rear fluid. It had a slight whine before the change, just as you let off the go-pedal between cruise and coast. Brand-new.
After the change to Royal Purple, it was a little quieter, but still there.
Later on, I had a leak at the cover (my own fault) and I changed it again.
This time, I used Mobil 1 75W140. NO NOISE.
I figure I'll use Mobil 1 from now on
I used Royal Purple 75W140 when I changed out my rear fluid. It had a slight whine before the change, just as you let off the go-pedal between cruise and coast. Brand-new.
After the change to Royal Purple, it was a little quieter, but still there.
Later on, I had a leak at the cover (my own fault) and I changed it again.
This time, I used Mobil 1 75W140. NO NOISE.
I figure I'll use Mobil 1 from now on
Elder User
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Senior User
Joined: Dec 2006
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From: Rhode Island
No, he means per quart. The Mobil1 75w140 is pricey at $17.99 a quart. It's weird because the Mobil1 75w90 in only $9-$10 a quart and the Royal Purple was the same price for either 75w140 or 75w90 at about $10 a quart.
I like to punish my wallet so I used the Mobil1 75w140 when I installed my new diff cover a couple of months ago. I hope the extra $32 dollars over the Royal Purple was worth something.
Posting Guru
Joined: Apr 2004
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From: Georgia
Postmaster
Joined: Apr 2005
Posts: 2,759
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From: round rock, tx
75W-90 gear oil for front diff
75W-140 for rear diff with LS friction modifier if needed, not always needed with synthetic
I used Mobil 1 gear oil
Amsoil is highly recomended
Royal Purple is also well endorsed
75W-140 for rear diff with LS friction modifier if needed, not always needed with synthetic
I used Mobil 1 gear oil
Amsoil is highly recomended
Royal Purple is also well endorsed
Elder User
Joined: Aug 2008
Posts: 505
Likes: 0
A little trick I learned from an old engine builder is to put a thin layer of RTV on each side of the paper type gasket and DO NOT let any residual fluid leak out onto the gasket before you get it bolted up. If the paper gasket gets soaked it will definitely leak. Then youre stuck doing it again.