My differential seals are weeping, time to open it up, clean it out, and re-seal it. My question is this - I intend to go synthetic, but I don't know how to handle a limited slip Trac-Lok differential. With traditional gear lube, you add a friction modifier. How does this work with synthetic ?

Synthetics have the friction modifier included in the additives package AFAIK for all the major brands. No additional needed for Mobile1 or Royal Purple, not sure on others.

I change my own differential oil with Mobile 1. Is there a big difference between Royal Purple and Moblie 1? Not to steal your topic, just wanted to know. THANKS, still the new guy.

I have read that adding friction modifier to these synthetics doesn't hurt, and that in some cases is needed - Amsoil is one (not that I care about Amsoil one way or another). They say you don't need it, but that you may want to add it anyway. I have no experience with it myself, though, hence my question.

Good question from Timmy, I'd like to know as well.

Jeff,

If you are concerned, adding the slip-lok stuff won't hurt anything, and it's the safest route.

Jeff and Timmy,

I use Mobile1 in tranny, diff and engine because they have actually been submitted for testing by the oil sanctioning body as evidenced by the little circle with grade/class info. Royal Purple just says they meet or exceed, but it's their word against your warranty. I don't put a lot of stock in racing history proving oil quality as it's changed much more frequently then we would do when in a racing motor.

I do use Royal Purple in the t-case, against my previously stated prejudice, because there's enough real world data by Jeep users to support it's quality...and ATF +4 has been hard to find until recently. Now that ATF +4 can be gotten without a 2nd mortgage and a visit to the dealer
I'll use it.

I do not use Mobile1 grease because the carrier oil drops out of suspension and makes a red oily mess around your grease gun and anyplace it's been squirted. I use Green Grease, a synthetic that is a little stickier then M-1 and still meets same certifications. I get it at Advance Auto, $7 or $8 a tube as I recall.

I don't think I've ever been able to find independant testing data on Amsoil...lots of sites pop up on a search, and they are all sites dedicated to promoting and selling Amsoil, so I just avoid it completely.

My trash lock did not like the Synthetic - I only ran it a few months before it died and I switched to ARBs - which did specify which synthetic to use. The local shop where I get parts said that they were seeing alot of trashlock failures with synthetic and were recommending that we stick with the standard stuff and put modifier in.

Once I switched to ARB lockers I always ran sythetic.

In what way did your Trac-Loc die, and how did you notice ? Reason I ask, is I have seen some stories of limited slip not working with synthetic unless the friction modifier was added, anyway, contrary to claims. And even so - I wonder how many mild off-roaders would even notice if their limited slip didn't work anymore, and hence, think synthetic was just fine.

I guess it comes down to this, even higher level question - is it ultimately worth it to go synthetic in the drive train at all ?

A piece of the clutch pack (?) about the size of pen top broke and popped out - it made
a tik-tki sound so I pulled the cover and out came a shard of metal about half an
inch long ...

I had all the parts to upgrade to an ARB so - by by trashlock - thank g__ for ARB.

The only thing that I did was switch to the synthetic oil - at the time I was on dirt
roads.

Do I know it was the sythetic - NO - but I asked all the local shops if this was a
problem and at least three said they were not recommending synthetics for the trashlock
at that time . Now maybe they have a friction modifier that works with the synthetic etc.

As far as synthetic oils go - I use them in everything - TORCO for the drive train and
Mobil-1 or Castrol for the engine. Use the GREEN grease also - does not melt here in
AZ like Mobil - everything melts here in the summer. Sometimes I have ground temps
in the parking lot that are almost running temps.

My engines that I have used good filters with and sythentics and most of them
are still going at 250K or more. A 100K of off-roads use is killer stuff here
and not uncommon for someone like me with time and a good gas credit card.

Thanks, AZ.

Not to change anything, azjeeper2000 what's green grease? I am out here in the desert too and it does get hot. When I lube the jeep I have noticed that the stuff does seem to melt in the summer Thanks

Green Grease = good stuff. Get it here!

I'll get some this week, I'm over due to lube the jeep. I did some checking on my own, there are a lot of good reveiws on the stuff.
"Muchos Grassass"

I know this will sound like treason, heresy, or just plain stupid, but here goes. When I installed my Currie kit, I added in a bunch of grease fittings. Some are pretty difficult to get grease guns over. Last year before Utah, I started greasing them but other things got in the way (like naps.) So when I got out there I just drove down to the quicky lube place (kind of across from Moab's McDonalds.) They didn't charge much and the guy that did it hit every fitting! And I watched him ooze out my drippy Mobil1 red stuff. Yes, anything that doesn't separate is better.

But just trash quality old lithium grease, the stuff that doesn't cost hardly anything is good. The trick is to lubricate every fitting several times a year. It doesn't take a lot of grease each time, it takes a lot of times.

Doesn't sound like treason at all to me, Dick. Personally, I have in the past only used synthetic in the engine, and then only because I change my oil at 6 months or 6k miles, I need good longevity. I have better things to do, and spend money on, than obsessing over chemicals. This time around, I need to get into my axles, and I thought I'd investigate if synthetic was actually a real beneficial choice, versus an emotional crutch.

quote:

eply



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One of the best tools I have is an air-grease gun - with that and the green grease I hit everything any time I want....

I have a CV drive shaft and that gets a shot every 1500 - other stuff I do two to four times a year depending on what I'm doing. Out here putting too much grease in some of the rubber fitting can cause them to overheat and explode ...

I have yet to run out of my first supplie of GREEN - it does not melt in the gun - so I don't waste alot like i did with Mobil - that just melted away and I'd have to reload - AGAIN - and AGAIN ... Used
to keep the stuff in my fridge .

quote:

Originally posted by azjeeper2000:

One of the best tools I have is an air-grease gun -

Actually, air grease guns are a pain. You have all the noise of the compressor running, and then the fat cord follows you everywhere, except when it gets snagged under a tire and doesn't follow.

If you want a better approach, Lincoln, the welder people, sell a nice cordless grease gun. I've got one, and its great for just walking out in the drive, or where ever you need to go and give it a shot or two.

I still find that for my off road jeep, I feel better about letting the quickylube guy do it. Then I know I've got fresh grease behind every fitting just as I'm hitting the desert, not after a 1600 mile drive.

Dick,

As long as you get lucky and find somebody with the integrity to do every grease fitting at the goofy-lube...great! I've seen to many problems on mine and others to trust 'em anymore. You have the same lube luck back in KY?

Yes, the air powered grease gun is fantastic! I hit everything when I have the Jeep jacked up while changing oil and rotating tires. Easy to just roll on my creeper from front to back and catch all the grease fittings. Hose is a little easier to manage that way, but cordless would be better...didn't have that option when I got mine.

My opinion when it comes to grease is anything is better then nothing, so as long as you squirt some into the fittings occasionally life is good. Since I'm taking the time to do it I may as well use synth as I know it's better. You'll believe once you see the way Green Grease sticks and maintains it's composition. No oil dropping out, no hardening and hiding in boots instead of lubricating joints...good stuff.

The air compressor is so much of a high value
tool that one more - grease gun - is minor - I
would not be able to keep my jeeps running without
air tools - I like a five minute tire rotation - and about every month I run into something that I
would not be able to do without the air tool - my
350 ft/lb Wammy gun jumps to mind.

But whatever your method - don't ever trust JIFFY *&^%$# with your jeep - and thus your life.

My question for you is: Since you got the diff cover off anyhow, and you're putting out the money for the synthetic, why not just put in a lunchbox locker, like a lock-right?