Differential Fluid Change

Bexar80

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I was going to drain and refill the rear diff with Mobil1 75w-140. It is listed to contain limited slip additives but also notes factory additives can be added. SO should I still add in the Mopar lsd additive or will just the Mobil1 fill be okay? I couldn't find a good answer after searching.
 
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JoelW

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The Mopar shop guys suggested the additive too if you don't use their fluid. I think the Mopar stuff in Castrol Syntec but I put the additive in too when I changed the fluid last year. I just put in a new rear gear and used the additive on JonB's advice. He has some lube that says you don't need additivie but recommended its use with anything else. Better be safe than sorry.
 

JonB

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I was going to drain and refill the rear diff with Mobil1 75w-90. It is listed to contain limited slip additives but also notes factory additives can be added. SO should I still add in the Mopar lsd additive or will just the Mobil1 fill be okay? I couldn't find a good answer after searching.


The Year Matters......... I hate to risk the ASSumption that the FORUM matters!

Gen 1-2-3 with OE diffs, REQUIRES the friction-modifier additive; Some very few oils (SynGear) has the additive included. MoPar oils (Castrol) do not.

Gen 4 OE GKN Visco-Lok only needs additive every other change! Really...

And diffs with Quaiffe or OSGiken do NOT require the additive/modifier.
 

plumcrazy

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yup, dont forget the modifier. it does name a difference. i always use the factory fill on this
 

Roy

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I filled her up last week with the OEM products. (I have an original drain plug on my 92, you probably don't, LOL)
 

RT/ED

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You may want to check the manual on the viscocity range of your differential fill. I believe the 75w-90 is for the transmission. I believe you should be using 75w - 140 for the differential ???:dunno:
 

Roy

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You may want to check the manual on the viscocity range of your differential fill. I believe the 75w-90 is for the transmission. I believe you should be using 75w - 140 for the differential ???:dunno:

I think he's right, Tator told me:
Diff: 75W-140 synthetic diff fluid [#4874469] 2 quarts and 4 oz "Limited Slip Additive" #4318060AB.

so that's what I've putten in there.
 

Dom426h

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On the Viper I go with the factory fill w/modifier to make certain my diff is performing as designed. Wouldnt want to have a fluid that might cause her to slip to much or not enough.

From what i understand if the diff fluid is too slippery than the limited slip will slip too much not giving you as much traction to one of the rear wheels.
In contrast: a fluid that is not slippery enough(for example one without the friction modifier) the limited slip will not slip enough causing her to bind up and hop/slip one of the rear wheels when going around a tight turn.

On my Dakota it calls for the same stuff but i have used the Mobil1 with a HALF bottle of the moparlimitedslipmodifier. Works fine from what i can tell. So thats what i would recommend if youve got a couple bottles of the Mobil1 stuff and want to put em to use.
 

dave6666

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What exactly in the reason to change from the factory fill? Is there a problem that is being solved? Is something broken that need fixing? Can anyone supply supporting evidence or documentation or research or whatever that states what was bad or broken and now it's fixed or better?
 

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