Rear diff fluid

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Feb 14, 2006 | 05:15 PM

jimkidd

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From: Greater Floyd Area, AR

Rear diff fluid

What would anyone recommend for rear diff juice for a 1 ton dually?

jimbo

Feb 14, 2006 | 05:26 PM

barebackjake

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From: STEPHENVILLE,TX!!!!!

i run the amsoil 75-90 extreme duty oil. love it the diff runs cooler with that than the dino oil

Feb 14, 2006 | 05:51 PM

1997F-350

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From: SHELTON, WA

i run royal purple 75-140 or 90 (cant remember) synthetic gear lube. it already has the friction modifier in it too if you got a ls rear.

Feb 14, 2006 | 07:03 PM

barebackjake

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From: STEPHENVILLE,TX!!!!!

75-90 is what the manual says.....

Feb 14, 2006 | 08:58 PM

RubberDuck

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From: Marble Falls, Texas

I just changed mine. I went with the Amsoil 75-90 extreme duty. I didn't use any friction modifier and my LS is still smooth as silk. I would go with the Amsoil.

Feb 14, 2006 | 09:11 PM

cookie88

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From: Cabot, Arkansas

I wonder why the manual changed, given the relative few differences between the OBS and NBS trucks. The 99+ service manual cals for synthetic 75w-140. I currently run the Amsoil in mine, but it's getting a bit chattery of late. It's almost due a fluid change so I'll probably go with the Red Line heavy shcockproof, or Royal Purple this next go around.

The 75w-90 is easier to find if that has any bearing on your desicion....nobody local carries the -140.