another front/rear axle question

chetos · **Posted:** Fri Oct 13, 2006 1:45 pm

I was getting my oil changed and was asked if I wanted to get my fluids changed. I said no but would look to reschedule and inquired about the price. They guy says it will be $50.00 bucks an axle because Liberties don't use synthetic lube. That's not right is it?? I smiled and said I'd call him to set it up. I am afraid to now.

unixxx · **Posted:** Fri Oct 13, 2006 1:56 pm

I'm pretty sure that the standard lube in the front (80W-90) and rear (75W-90) isn't synthetic. If you get the heavy duty lube for towing (75W-140) it is synthetic. At least this is what the parts guy at the dealership told me. I bought synthetic 75W-140 for the front and rear from the dealership but think I might get better quality fluids now that I'm actually going to regear and install a locker.

Elwenil · **Posted:** Fri Oct 13, 2006 2:19 pm

The front is normal 80W-90 gear oil but the rear is synthetic 75W-90 or for towing, synthetic 75W-140. Limited slip additive is required for axles with the limited slip differential.

unixxx · **Posted:** Fri Oct 13, 2006 2:31 pm

Elwenil,

Can you use synthetic 75W-140 in the front Dana30a?

Elwenil · **Posted:** Fri Oct 13, 2006 2:48 pm

From the factory's point of view, I'd say no since they don't give me the specific option to use any other fluid in the front. From my own experience, I'd say that it would do the job just fine. Even though it is listed as a much thicker viscosity fluid, synthetic is designed to flow much more freely than petroleum fluids in the cold, so I think it would be a decent swap.

Jeepjeepster · **Posted:** Fri Oct 13, 2006 4:40 pm

unixxx wrote:

Elwenil,

Can you use synthetic 75W-140 in the front Dana30a?

lol, I hope so, b/c I did.. :wink:

Ive read before that its recommended to use syn in the front actually.

Skyjump136 · **Joined:** Tue Jul 05, 2005 6:50 pm **Posts:** 1633

Jeepjeepster wrote:

unixxx wrote:

Elwenil,

Can you use synthetic 75W-140 in the front Dana30a?

lol, I hope so, b/c I did.. :wink:

Ive read before that its recommended to use syn in the front actually.

Yes, 75w-140 is recommended for the front. I am using it in both axles actually. PM JJSKJ and he can get you the prices from Amsoil. I saved a bundle by going through him.

Edwin · **Posted:** Fri Oct 13, 2006 9:21 pm

If I remember right, my owners manual says synthetic for the front and synthetic for the rear if you tow.

Loopkey · **Posted:** Fri Oct 13, 2006 10:07 pm

Here is the section for axle fluids for 2002 KJ's:

DESCRIPTION - AXLE
A multi-purpose, hypoid gear lubricant which conforms
to MIL-L-2105C and API GL 5 quality specifications
should be used. Mopar Hypoid Gear
Lubricants conforms to these specifications.

FRONT AXLE
- Lubricant for 186FIA (Model 30) axle is SAE
75W-140 SYNTHETIC.

REAR AXLE
- Lubricant for 198RBI (Model 35) axle is SAE
75W-140 SYNTHETIC.
- Lubricant for 8 1/4 axle is a thermally stable
SAE 75W-90. For trailer tow or heavy duty applications
the lubricant should be replaced with SAE
75W-140 SYNTHETIC.

NOTE: Trac-lokT equipped axles require a friction
modifier be added to the lubricant.

CAUTION: If axle is submerged in water, lubricant
must be replaced immediately to avoid possible
premature axle failure.

unixxx · **Posted:** Sat Oct 14, 2006 1:37 am

That's funny, they must have changed the spec along the way. My 05 service manual lists 80W-90 in the front and the only time it mentions synthetic at all is 75W-140 in the rear for towing.

Elwenil · **Posted:** Sat Oct 14, 2006 10:38 am

Hmmm, that's odd but not unusual. My chart lists regular 80W-90 for the D35, part number 4874468, Spec MS-9020. For the 8 1/4" rear it lists 75W-90 part number 5010320AA, Spec MS-9763 and then also lists "For Heavy-Duty or Trailer Tow applications, Synthetic SAE 75W-140 GL-5 part number 4874469 Spec MS-8985, which oddly enough is also what a Viper D44 rear takes.

another front/rear axle question

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