06 Differential Fluid Change Question

lutzms · **Joined:** Thu Sep 02, 2010 9:58 pm **Posts:** 10

Few general questions that I’m hoping I can find some answers to (the forum has been great so far)! I know this topic has been posted quite a few times, but I’d like people to chime in on changing out the rear differential fluid on my 2006 4x4 that I picked up a few months ago. I’m not sure of the maintenance of the Jeep prior to picking it up, but my guess is the fluid has never been changed (has 87,000 miles). I'm sure I'll have more questions once I start looking at transfer case and front differential, but right now I have a few questions about the rear.

I live in northern Wisconsin, so we have cold winters, and hot summers. Based on the relative extremes in the temperatures, is there a best “all around” fluid that I should be looking at? Also, I don’t currently have a hitch for towing, but this summer I hope to be able to add one. I won’t be towing on a regular basis, but will occasionally be hauling my snowmobile or boat for trips around 100 miles or so. Should I still be looking at a fluid such as 75W-140 that is recommended for vehicles with the factory tow package given that scenario, or would something else be a better fit? 95% of the vehicle use will be highway/city driving.

I’m also wondering about the brands on the market. I narrowed it down to RedLine or Amsoil synthetics, but I haven’t read many reviews of people using RedLine in their Jeeps (I’ve seen quite a few reviews of it being used in light trucks/other SUV applications). Amsoil has been covered quite a bit. From what I’ve read people generally like Amsoil, but there have been a few that say they have had bad luck with it (just like any brand really). From RedLine I haven’t read any negative reviews at all, but I’m sure they’re out there. I found it funny that Amsoil didn’t test the RedLine fluid against their product like they do just about everything else on the market…that makes me think it might be an equivalent or better product at the same price point. Are there any thoughts on that? I'm guessing most will say I can't go wrong with either one, but if there are opinions on the RedLine product I'd like to hear them.

Sorry about the basic questions…I’ve never really done anything beyond the basic oil changes, brakes, etc, so I want to make sure I’m doing this right before I try to tackle it. Thanks for the help!

LibertyCRD · **Posted:** Wed Mar 09, 2011 1:04 pm

It's been discussed a lot on here...but synthetics are NOT what you want. The cheap regular "dino" gear oil from the shelf at Walmart works better in these diffs. especially if you have Trac-Lok. Remember to use additive too if so.

JJsTJ · **Posted:** Wed Mar 09, 2011 10:45 pm

75w110 in the front and rear diffs in all 4 of our Jeeps, TJ, XJ, SFA KJ and IFS KJ. No problems to speak of. mine was used (prior to SFA) to tow a large tent trailer back and forth to Moab w/ a stop in Grand Canyon w/ no abnormal wear showing after that trip or any of the use before or after to include lots of wheeling.

I call BS on not using syns in diffs and I've not seen any good info to the contrary. Syn fluids work great anywhere they have been used. Will dino work fine too? sure it will.

fwiw, Redline was compared in the 75w90 testing: https://www.amsoil.com/lit/g2457.pdf

Billwill · **Posted:** Thu Mar 10, 2011 2:41 pm

If your Jeep has a Limited Slip Diff at the rear, make sure you add the required additive for the friction clutches after re-filling with new oil

tjkj2002 · **Posted:** Thu Mar 10, 2011 2:43 pm

Billwill wrote:

If your Jeep has a Limited Slip Diff at the rear, make sure you add the required additive for the friction clutches after re-filling with new oil

Actually you want to add the friction modifier 1st then put in the new gear oil.

mikey1273 · **Posted:** Thu Mar 10, 2011 7:51 pm

I dont think Track-LOk was an option on 2006's Mine does not have it

I used 75w90 synthetic in the rear and I think 80w90 in front what ever the manual said. I think it calls for 75w140 synthetic in the rear if you tow. I don't tow much or many heavy loads so I did not go with that. If I ever get a camper that will change. for now my towing is light stuff on a utility trailer like junk to the incinerator and furnature or a washer/dryer, well under 1000 pounds and only local.

lutzms · **Joined:** Thu Sep 02, 2010 9:58 pm **Posts:** 10

Thanks for all the replies...it's appreciated.

For towing, I won't be doing much heavy stuff on a regular basis...I think sticking with the 75w90 might be a better option. mikey1273 do you mind telling me which brand you went with?

Changing it doesn't look like it's too much of a chore, so I wouldn't mind doing it at the regular intervals if I did go with a non-synthetic (still on the fence about that).

On a related note, I was looking at the Fel-pro gaskets for the rear cover, and some people say they apply RTV to both sides to seal it, while others say they use a spray adhesive. Does anyone use the adhesive spray? Most of the articles/posts that I've looked at just show people using RTV and skipping the gasket all together.

JJsTJ · **Posted:** Fri Mar 11, 2011 5:23 pm

75w110 ftw. split the difference between the low and heavy weights for occasional towing.

tjkj2002 · **Posted:** Fri Mar 11, 2011 9:48 pm

lutzms wrote:

Thanks for all the replies...it's appreciated.

For towing, I won't be doing much heavy stuff on a regular basis...I think sticking with the 75w90 might be a better option. mikey1273 do you mind telling me which brand you went with?

Changing it doesn't look like it's too much of a chore, so I wouldn't mind doing it at the regular intervals if I did go with a non-synthetic (still on the fence about that).

On a related note, I was looking at the Fel-pro gaskets for the rear cover, and some people say they apply RTV to both sides to seal it, while others say they use a spray adhesive. Does anyone use the adhesive spray? Most of the articles/posts that I've looked at just show people using RTV and skipping the gasket all together.

The OCI for dino gear oil is 2-3 times longer then full synthetic gear oil in diffs,sometimes even longer.

mikey1273 · **Posted:** Sat Mar 12, 2011 2:49 am

I got Valvoline thats what napa had

I asked at the local Jeep shop and they said they usually use RTV... Mine is RTV but the gasket is like 4-5 dollars so I think either is fine as long as it don't leak.

huntbuggy · **Joined:** Sun Dec 19, 2010 6:24 pm **Posts:** 91

I bought a five gallon pail of 80W90 dino and saved huge bucks. I can do a few years changes at half the interval and still come out cheaper than one synthetic change. Sorry to synthetic buffs but for the price I don't think the "deemed benefits" are worth it.

Just did first 80W90 fill into new Ruffstuff diff cover last week and running smooth and quiet as expected.

:2cents:

lutzms · **Joined:** Thu Sep 02, 2010 9:58 pm **Posts:** 10

Going with a 5 gallon pail definitely is more affordable (valvoline 80w90 is going to 75 locally), and allow me to change at a shorter interval. You haven't had any issues running 80w90 both in the front and rear diff?

huntbuggy · **Joined:** Sun Dec 19, 2010 6:24 pm **Posts:** 91

lutzms wrote:

Going with a 5 gallon pail definitely is more affordable (valvoline 80w90 is going to 75 locally), and allow me to change at a shorter interval. You haven't had any issues running 80w90 both in the front and rear diff?

Just did the rear this time around because I was changing to a heavy duty differential cover, pail cost me $44.99. Found 85W140 plain dino for the front for $44.99 at the same place (store brand PetroCanada/Suncor oils) but they were out of stock when I went and the front isn't really due till summer. Highly recommend you shop around - I did here in Canada for a few days calling and visiting shops and found lots of product, specs and the best price in the end.

http://www.jeepkj.com/forum/showthread. ... post531471

Also found a place with pails of ATF+4 for transfer case, transmission (and steering for you newer KJs) for $52

If you have room for pails - and friends with 4x4s needing the same fluids - why not?!

KJ_Dave · **Posted:** Tue Mar 29, 2011 7:12 pm

I use a LubeLocker reusable gasket from 4wheel parts. It makes it really easy to change the rear diff on a whim. It's only $21.99. http://www.4wheelparts.com/Drivetrain-and-Differentials/Lube-Locker-Chrysler-8-25-Differential-Gasket.aspx?t_c=12&t_s=237&t_pt=4018&t_pl=9726&t_pn=LULLLRC825

06 Differential Fluid Change Question

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