Diff. Fluid Change Question

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Nov 4, 2009 | 07:59 AM

#11

saltman

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Joined: Jul 2007

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ronjenx is saying they fill with the 80/90 not the 75/140 from the factory. If that is true. It is not a factory synth fill.

I seem to remember it was different before. Could be wrong. You can check the tags on your difs. Pretty sure my 07 said 75/140 on it and they changed mid 07 or 08.

Nov 4, 2009 | 08:00 AM

#12

racer83l

JK Junkie

Joined: Sep 2007

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From: Long Island, NY

mine came with tow package from the factory and SHOULD have been filled with the 75-140. I use it all around since Im running 35's

Nov 4, 2009 | 08:01 AM

#13

saltman

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ahhh... that makes sense. towing package might be the key. I also use the 75/140. Royal Purple.

Nov 4, 2009 | 08:18 AM

#14

Hellbound13

Thread Starter

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Joined: Apr 2008

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From: Westchester, NY

I bought the 75w 90 mobil 1, I have no tow package am I okay to use that?

Nov 4, 2009 | 08:53 AM

#15

ronjenx

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Joined: Feb 2008

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From: Maine

Quote:

Originally Posted by Hellbound13

I bought the 75w 90 mobil 1, I have no tow package am I okay to use that?

Yes.

Nov 4, 2009 | 09:00 AM

#16

ronjenx

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Joined: Feb 2008

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From: Maine

Quote:

Originally Posted by ronjenx

Two people in this thread have said the original stuff in the diffs is synthetic. Could be, but I would have to see the bottle to believe it.

The MOPAR stuff is synthetic only if it says "synthetic" on the bottle.
Initially, they come with Mopart Gear & Axle Lubricant (SAE 80W-90) (API GL-5), which is a general purpose GL-5 gear oil. I don't believe it says synthetic on those bottles.

Quote:

Originally Posted by racer83l

here you go.

Thanks for verifying what I posted. I looked for a pic, but couldn't find one.

The Mopar Gear & Axle Lubricant (SAE 80W-90) (API GL-5), doesn't say synthetic on the bottle. Got a pic of that?

Nov 4, 2009 | 09:24 AM

#17

saltman

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Joined: Jul 2007

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Mopar 80/90 is not synth.

ronjenx - are you suggesting they put 80/90 in the difs with the tow package?

Nov 4, 2009 | 12:33 PM

#18

ronjenx

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Joined: Feb 2008

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From: Maine

Quote:

Originally Posted by saltman

Mopar 80/90 is not synth.

ronjenx - are you suggesting they put 80/90 in the difs with the tow package?

No. I made no mention of tow package. I have no idea if the tow package would include the recommended synthetic rear diff oil from the factory.

I was just saying one cannot assume the oil from the factory, or all bottles of the MOPAR stuff, are synthetic, unless it says so on the bottle..

Nov 8, 2009 | 11:27 AM

#19

dmwil

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Joined: Aug 2007

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From: Danville, Indiana

Does the Rubicon (locking rear diff) require Limited Slip Diff additive?

I'm getting ready to fill it with Supertech 75W-140 synthetic gear oil, and just need to know if I need to use the additive or not.

Thanks!

Last edited by dmwil; Nov 8, 2009 at 03:20 PM.

Nov 8, 2009 | 12:12 PM

#20

ronjenx

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Joined: Feb 2008

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From: Maine

Quote:

Originally Posted by dmwil

Does the Rubicon (locking rear diff) require Limited Slip Diff additive?

I'm getting ready to fill it with Supertech 75W-90 synthetic gear oil, and just need to know if I need to use the additive or not.

Thanks!

Quote:

Originally Posted by rickc309

I looked at my Mobile 1 diff fluid bottle, it says LS right on it. No addition additive needed.

The JK Rubicon diff is a locker, not a limited slip. Therefore, no additive is required.
You are correct, though, about the Mobil 1. If you had a limited slip, and were using the Mobil 1 stuff, you would not need the additive.

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