diff oils
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Freshman User
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diff oils
Im looking for what diff oils i should use. What weight, a good brand ect. The rear diff im not sure about. Its on a 2002 f-250 sd 4x4 with a 5.4 liter. Not sure which rear end it is and how to verify which it is. Any advice would be helpful. The same goes with the front diff
Post Fiend
Joined: Jan 2000
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From: Metro Detroit (Redford)
The manual will tell you the weight, but for brand I would go with Redline. Also even if the book says 75w90 you may be better off with 75w140. Remember these numbers are a different scale from motor oil and a 75 may be like a 30 weight--don't know exactly, but you can google and find out.
Hotshot
Joined: Jan 2004
Posts: 19,760
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From: St Louis
There is a tag bolted to the diff cover that gives your spec.
It likely says "75W-140 SYNTHETIC". Follow it specifically. If your axle is limited slip, add the correct friction modifier if not present in the base replacement oil.
The brand name is your personal choice. One is likely as good as any of the others as long as it meets or exceeds Ford's specification.
Steve
It likely says "75W-140 SYNTHETIC". Follow it specifically. If your axle is limited slip, add the correct friction modifier if not present in the base replacement oil.
The brand name is your personal choice. One is likely as good as any of the others as long as it meets or exceeds Ford's specification.
Steve
Posting Guru
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My Ranger (8.8, 4:10 gears, LS) calls for 80w-90 for both front and rear differentials. Would there be any benefit to using 75w-140 Mobil 1, or would I be better off using the 75w-90?
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Fleet Mechanic
Joined: Aug 2002
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From: Sioux Falls SD
Originally Posted by PW01
My Ranger (8.8, 4:10 gears, LS) calls for 80w-90 for both front and rear differentials. Would there be any benefit to using 75w-140 Mobil 1, or would I be better off using the 75w-90?
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Cargo Master
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From: Lynnwood, WA
Originally Posted by PW01
My Ranger (8.8, 4:10 gears, LS) calls for 80w-90 for both front and rear differentials. Would there be any benefit to using 75w-140 Mobil 1, or would I be better off using the 75w-90?
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Well i know the rear diff on my 02 f250 has 2 tags . Ill take another look tomarrow to see if i can read them at all. Hopefully itll give me the info im looking for. The transmission calls for regualr mercon. However i remember ford came out with mercon v to rid the problem of shuddering in the trans. Im know i should use reg mercon. But why would they come out with a new fluid for my truck to use the old fluid?
Freshman User
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Additional question,
From what it sounds like, if I have a factory limited slip that originally didn't have synthetic, and I and a quality synthetic it would be ok as long as I add the correct friction modifier to it?
From what it sounds like, if I have a factory limited slip that originally didn't have synthetic, and I and a quality synthetic it would be ok as long as I add the correct friction modifier to it?