Do my "diffs" need friction modifiers? - Jeep Wrangler Forum

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Old 08-26-2012, 12:10 PM   #1
DaWrangler's Avatar
Join Date: Aug 2012
Location: Da Region of NWI
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Question Do my "diffs" need friction modifiers?

HiYa, all, I just purchased a 98 Wrangler 2.5 4cyl. Auto with 123K. It is my first Jeep. It appears to be totally stock. I want to change the "diff" fluids but I do not know if they need the friction modifier added. I have no service records OR owners manual. (zzzzz) So I'm startin out from scratch. I do have a Jeep 'tip" card that was in the glove box stating the Wrangler has Command-Trac NV231 Part time 4wd. The front diff has a steel plug and the rear has a rubber one with dana on it. Any knowledge would be greatly appreciated. Also, what model danas are these?

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Old 08-26-2012, 12:24 PM   #2
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Location: South Africa
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From that brief description you look to have a d30 front and d35 rear. You need regular hypoid gear oil with nothing added. I believe mineral to best and I wheel it so I fill with 85W140 mineral oil. Mineral or synthetic API GL-5.

2003 Wrangler Sahara 4.0 42rle D30/D44
Front: 2" BDS coils + JKU shocks
Rear: 2" BB + Zone Nitro shocks
Zone 1.25" BL + 1" MML, UCF LoPro
32" BFG AT on 16" Racing Hart
Ramsey Pro Plus 6000, IPF 900s 130W
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Old 08-26-2012, 12:27 PM   #3
Knows a couple things...

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Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 38,518
The front axle never needs a friction modifier and the rear axle only needs it if it has the optional Tracloc limited slip differential.

However, probably 99% of the appropriate GL-5 gear lubes already contain friction modifier for use by a limited slip differential. The additive is compatible with all axle types with or without a limited slip differential so most lubricant manufacturers include it just in case the vehicle has a LSD.

You can verify if the gear lube has the friction modifier by looking on the label on the back of the bottle and looking for wards to the effect of 'compatible with limited slip differentials' which means it contains the friction modifier additive.

Your Jeep has a Dana 35c in the rear and a Dana 30 in the front.
When you have a choice, buy American.

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