Differential Lubricant

I doubt VERY seriously it takes anything unusual... any good quality GL-5 or GL-6 gear lube should be fine. 75W-90 is a good viscosity for most axles for just about anything other than heavy towing.

Jerry

What does the Rubicon owner's manual recommend? I'm putting a Rubi Tru-Lok in my Cherokee rear, so I'm curious to know.

Steve

Ice wrote:

iirc it is standard gl5 gear oil and dc's limited slip friction modifier added to it, though it seems weird that they would call for this since the rubi differentials doesn't have clutch packs like the other wrangler limit slip. I think they also called for the friction modifier in the front axle too, but i might be wrong. I'll consult my fsm tonight at home - I also have an 03 rubicon.

-jd

I disagree. The rubicon also has a limited slip in the rear. Barring any special need due to the lockers (I can't speak yes or no to that), it is likely the limited slip may require a special additive, much like my rear D44 w/limited slip does. It may not, since it uses a different kind of limited slip (no clutch packs?) than mine, but I would want some definitive answers on that before just throwing regular gear oil in there and calling it done.

The Rubi's rear limited slip differential is gear-based, not clutch-based, so it has no need for the friction modifier needed for clutch-based LSDs like the Tracloc.

Jerry

It does not require anything special because of the lockers, it does have a requirement for special lubricant for the limited slip though.

The Rubicon's limited slip is gear-based Jeff, like the Truetrac. And so far as I know, like the Truetrac, it does not need any kind of additive or special lubricant. Some know-nothing tech-writer (ahem, you know about those guys ;) ) within Jeep may think it does because of the clutch-based Tracloc used in other Jeep models, so some Jeep publication may indicate the need but all indications say it takes straight GL-5 or GL-6. :)

Jerry

-- Jerry Bransford To email, remove 'me' from my email address N6TAY, PP-ASEL See the Geezer Jeep at

What about those who have the 8.25 with Trac-Loc, Jerry? I'm going to change the diff fluids here this weekend and should I buy the additive from the dealer or could I get something better from the parts store?

I was thinking about using a synthetic oil too... would I still need to add some type of additive? As always... TIA.

-- Taylor

'89 Audi 200 '03 Audi S6 Avant '98 Jeep Cherokee Sport

Taylor, it's extremely hard to find a GL-5 lube without the additive needed for the Tracloc already in it. That'd be all you would need. The back of the bottle will generally say something like "compatible with most limited slip differentials" which means it has the friction modifier already added. Sometimes you may need to add a tiny bit more on top of what comes in the GL-5 gear lube, but that's almost pretty rare. The additive is actually useful for other needs as well like helping new R&P gears run a bit cooler during break-in.

Jerry

How does the additive work? Just curious. Nick

Ok. That's kinda what I thought might be the case. But I would definitely have been leary to just ignore using the friction modifier without people posting here who have more expertise in that area. ;-)

Bill, you said something about that the additive makes it so the diff will SLIP...does that mean that without the modifier a clutch-pack LSD would bind up and no longer slip in differential action anymore? I've always wondered what exactly the modifier did and what the consequences of forgetting to use it might be...

Yeah, I remembered that right after I hit the Send button.

But, the point is still the same, the locker does not require any special lubrication, and the lubricant that we normally would put into a limited slip with clutches will work just fine in the gear based limited slip. So, even though I was technically incorrect when I said it requires a special lubricant for the limited slip, the fact is that the limited slip lubricant is readily available in any auto parts store. And, it turns out that there is no demand for special lubricant for the limited slip or for the locker, which is pretty much what I already said. Remember, the original poster was concerned that he needed special lubricant for the LOCKER, not the limited slip. It might cost a little more for the lubricant that the clutch-based limited slip needs, but this lubricant ought not be a problem for the gear-based limited slip that the Rubicon has. The original poster wants to do the job himself, but the dealer is filling him with a load of crap. There is no reason the original poster can not do this job himself.

Jerry, I think I just ranted at you the same way I rant at Bill after he nit-picks an irrelevant bit of minutia.

clutch-based

Heh, I know you too well Jeff to have considered it a real rant anyway. :) Hey, are you going to TDS? I think I might be going with a group from the JeepForum.com group and it'd be great to wheel with you. I'm thinking of doing Pumpkin Eater this year for grins.

Jerry