Rear differential fluid

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07-18-2018, 08:08 PM

09Larriat

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Rear differential fluid

I am getting ready to replace my rear diff fluid and just wondering if everyone uses the ford friction modifier at about 50 bucks Canadian on amazon or just use Lucas or Royal Purple 75w140....they both say they contain the friction modifier already in there. Oh yeah, limited slip differential not electronic locker...I pulled my 4x4 **** off checking to see if it clicked.😔

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07-22-2018, 09:02 AM

mueckster

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I would use the fluid with additive in it and give it a try. If you have clutch chatter' afterwards, you can always add the additive later. Just leave the level down slightly, until you determine if you need more friction modifier, then add; or top off with more fluid.

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07-22-2018, 11:20 AM

2jhanna

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It is my understanding that the GL5 gear oils that have the additive built in, which many major brands do, have the additive at the proper ratio. Meaning that no additional additive is needed. Also, a side note is that this built in additive doesn't hurt when used in an open diff, where it's not really needed.

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