Help WITH MY DIFFERENTIALS

**Snake Man** · 10-04-2006, 09:27 PM

OK people my dealer says its time to change my diff fluids and wants $100. each. I think I can handle this myself but I need some advice on materials. Is 80W-90 gear lube correct, if so what brand? I've got 2 bottles of limited slip additive to put in each diff. Does the front and rear use the same materials? Even though I'm a long time Jeep owner, this 05 Rubicon is new territory.
THANKS

**Rocky529** · 10-04-2006, 09:29 PM

http://www.4x4xplor.com/diff-service.html

**Jerry Bransford** · 10-04-2006, 09:29 PM

Your Rubicon does not have the type of limited slip differential in the rear that requires any type of limited slip additive, you can return those two bottles of additive for a refund. 80W-90 is fine, I would just go with a major brand of synthetic gear lube like Valvoline, Mobil-1, etc.. Besides, all of those already contain the limited slip additive which while not needed by either of your Rubicon's axles, won't hurt in the least.

**Snake Man** · 10-04-2006, 09:40 PM

OK GUYS
I think I have the mechanics part down pat.
Why would my service manual say to use a additive if it doesn't need it. I also though that the rear was a air locker and a limited slip. Please clarify.

**Jerry Bransford** · 10-04-2006, 09:44 PM

Quote:

Originally Posted by Snake Man

OK GUYS
I think I have the mechanics part down pat.
Why would my service manual say to use a additive if it doesn't need it. I also though that the rear was a air locker and a limited slip. Please clarify.

YES the rear axle has both a locker and a limited slip but the type of limited slip differential used in a Rubicon does not require a limited slip additive. Clutch-based limited slips like the Tracloc used in standard Wranglers require the additive. Your Rubicon's limited slip is gear-based so, once again, it does not require a limited slip friction modifier additive. But don't forget as mentioned above, most gear lubes already contain the additive anyway... your Rubicon just doesn't need it.

**Snake Man** · 10-05-2006, 07:29 AM

Thanks for the info Jerry. As for RTV, Jeep says to use the GRAY and I've always used BLUE. Does it matter?

THANKS

**Jerry Bransford** · 10-05-2006, 09:10 AM

Quote:

Originally Posted by Snake Man

Thanks for the info Jerry. As for RTV, Jeep says to use the GRAY and I've always used BLUE. Does it matter?

THANKS

My personal preference is Ultra Black from Permatex. Most everyone I know has used black for years too, never a leak when I have used it.

**neZZr** · 10-05-2006, 09:53 AM

DC specifies 75W-140 synthetic for the Rubicon axles... limited slip additive not needed.

Materdaddy · 10-05-2006, 11:15 AM

Quote:

Originally Posted by Jerry Bransford

My personal preference is Ultra Black from Permatex. Most everyone I know has used black for years too, never a leak when I have used it.

I second the use of the Ultra Black Permatex stuff... works great for diffs among other things!

**blktjjp** · 10-05-2006, 01:24 PM

Give some consideration to Lube Lockers, They cost but are well worth it in my opinion.

BigJeepJay · 10-05-2006, 01:26 PM

Quote:

Originally Posted by blktjjp

Give some consideration to Lube Lockers, They cost but are well worth it in my opinion.

Every experience I have had with Lube Lockers have been bad as they are expensive and only can really be used once. Half the people I know who have tried them have had problems with them leaking. RTV is cheap, effective, and easy.

**blktjjp** · 10-05-2006, 01:40 PM

Wow, well I guess i'll keep my silly mouth shut since that appears to be the definative word on Lube Lockers.

**neZZr** · 10-05-2006, 01:45 PM

I just pulled my rear cover last night & re-RTV'd it because it was leaking... it's a touch awkward holding the cover up there without smearing the RTV all over until you can get a couple bolts in... but it's not worth the cost of a Lube Locker even if it did seal as well.

purplewindworm · 10-05-2006, 01:55 PM

What's wrong with just using a gasket? Seems alot easier and more reliable to me. I am gonna change my diff oil in a week, never done it before. thanks for the web link of step by step instructions.

TheTwins · 10-05-2006, 01:56 PM

I have two comments.

1. If you have a Rubi, you need 75W140 for the rear diff (helical LSD)
2. If you have a Rubi, you don't need to pull the covers and mess with gaskets / RTV / etc. (they have drain plugs)

10-04-2006, 09:40 PM	#4
Snake Man 43 Years with Jeeps Join Date: Nov 2005 Location: Phoenix, AZ Posts: 65 Profile Gallery Classifieds My Jeeps	OK GUYS I think I have the mechanics part down pat. Why would my service manual say to use a additive if it doesn't need it. I also though that the rear was a air locker and a limited slip. Please clarify.

10-05-2006, 07:29 AM	#6
Snake Man 43 Years with Jeeps Join Date: Nov 2005 Location: Phoenix, AZ Posts: 65 Profile Gallery Classifieds My Jeeps	Thanks for the info Jerry. As for RTV, Jeep says to use the GRAY and I've always used BLUE. Does it matter? THANKS