D44 oddities

[ftpiercecracker1]

#1 What is this, is this how its supposed to be and how do I remove it?

 

 

 

 

 

 

#2 Again, what is this? RTV? No lip seal?

 

 

 

 

 

#3 do trac-lok lsd use a spring in the middle? Mine is missing if so. Could I add one?

[Pete M]

the first is a roll pin used to hold the center pin in place.

[mjeff87]

Roll pin, like Pete says 

 

No inner axle seals on D44's, the diff oil lubes the outer axle bearings.

[ftpiercecracker1]

Thanks guys. I figured out the roll pin pretty quickly when I saw there was a corresponding hole on the other side. Was really worried some dunce had broken the bolt off.

 

 

If there is no inner seal the what is the orange stuff? Factory rtv to seal the tubes to the housing?

 

Also what about the LSD spring? I really would like an answer for that. How do the clutch packs get pushed together if there is no spring? I assume under load the spider gears probably put side load on the carrier, but would adding a spring (if possible) help or would it inconsequential?

[Pete M]

doesn't appear to have a spring 

 

 

[Eagle]

21 hours ago, ftpiercecracker1 said:

Also what about the LSD spring? I really would like an answer for that. How do the clutch packs get pushed together if there is no spring? I assume under load the spider gears probably put side load on the carrier, but would adding a spring (if possible) help or would it inconsequential?

 

No springs. The clutches are pre-loaded by adjusting the shim pack. The original Trac-Lok in my 88 XJ finally gave up the ghost ate around 150,000 miles. The guy whose stock car I used to crew on was also the service manager at my Jeep dealer, and prior to becoming service manager he was their top mechanic. Instead of buying a new Trac-Lok unit, he re-shimmed it and I got another 50,000 miles out of it.

 

The downside to a Trac-Lok is that it IS always engaged ... until the difference in torque from one side to the other becomes great enough to overcome the friction in the clutches. That's what happens when you go around corners on dry pavement.

[ftpiercecracker1]

Eagle, it sounds to me like the trac-lok is best for slippery conditions (mud) and not necessarily for when one wheel is entirely free spinning (rocks).

 

It was my understanding that when torque is applied the spider gears compress the clutches by virtue of them trying to cam away from the center of the carrier. Is this how it works? 

 

Also your comment about expected milage is making me regret buying a rebuild kit. I think the one is this axle only has about 50-80k. Although I don't know what sort of life it had. To my inexperienced eye the clutches looked OK. New clutches were only $80 so I guess it's not to bad.

[Eagle]

Clutch type limited slip differentials are really intended for street driving in rain and snow, not for hard-core wheeling and rock crawling. They aren't "lockers," they are what they are -- slip limiting devices.

 

A better type of limited slip for off-road use is the Torsen type, which is mechanical. The Tru-Trac is similar to that; it's an all mechanical differential, so it doesn't require the use of friction modifier. That's what I have in the rear of my 88 MJ Chief, and it works very well. It's transparent on the road -- you don't even know it's there -- but it has worked well wheeling with NAXJA-NAC at the old Paragon Off-Road Park in Pennsylvania, and in snow on the street. I don't think it's robust enough for really big tires on slick rock such as at Moab, though.

 

The life span of a Trac-Lok depends partially on how much abuse it gets, and also on whether or not you maintain the friction modifier.

 

It was my understanding that when torque is applied the spider gears compress the clutches by virtue of them trying to cam away from the center of the carrier. Is this how it works?

 

A Trac-Lok defaults to being engaged. The clutches are in contact all the time. They allow the two wheels to rotate at different speeds only when the torque differential between the two wheels exceeds the limit -- such as when going around corners on dry pavement. In other words, it's "locked" until there's enough torque to make the clutches slip. The limited slip diffs in the WJ Quadra-Trac system work just the opposite. In that system, it's still a clutch system and requires friction modifier, but it defaults to being UNlocked. When the speed difference between the two wheels exceeds some limit, a "gerotor" pump in the diff applies pressure to engage the clutches. I always wondered if we could retrofit the Quadra-Trac diffs to XJs and MJs, but I've never had the time or money to pursue it.