How to tell LSD, Locker or None

Hey,
I'm trying to get more acquainted with my so I have a question. To explain, the fellow I bought my 1992 Cherokee from was more of a "for show" guy and honestly didn't know much about it mechnically. He was seemingly convinced he at one time got some type of "locking device" install. I jacked up my rear and set it on jackstands to find out about it. When I put it in neutral and spun a tire, the other tire went the same direction, what exactly does this tell me?

Thanks,
Kevin

That it more than likely has a traction device in the rear, did the front do the same ??? On a normal Open diff the one tire will go one way the other tire the other way. There might also be a small metal tag on the diff. What you need to find out is what kind of LSD is back there and the only way to tell is ask the previous owner where he had it installed then go there and ask them. Second method it it was factory is to go to a dealer with the vin number and have them run it, the printout the build sheet, that will show every option that came with it. The reason you need to know is that some LSD's [Limited Slip Devices] need an additive when you change the differentials oil, most full lockers do not...
An anecdotal way to tell if it's a detroit is to do a few sharp turns in a parking lot and listen for a loud bang as the rear locks up and unlocks going around corners

That would indicate either a limited slip diff or a locking diff.

If it has a tag on the diff cover that says..."use limited slip additive" well... lacking that, the only way to tell for certain is to pull the cover (when you refresh the lube) and look for clues:

If it is a Track-Lok (clutch type limited slip) you will see side & spider gears in the center just like a normal open diff. The clutch/spring packs will be outboard of the side gears. You will need a small bottle of "friction modifier/L-S additive" (from the Jeep dealer) to add to the gear oil if you have one of these diffs.

If it is a Detroit EZ / LockRite / Aussie there will be no side/spider gears inside the diff case...but that space will be filled with the locker, a multi-piece silvery-colored thingy with squared off gear teeth between the sections.

Id refer you to www.tractech.com to determine if it's a True-Trac or Detroit Locker...been so long since I've looked at my D30 TruTrac that all I remember is it's smooth & silvery looking... I think ya could see the helical gears (barber pole cut) in there, but I may be on dope.

RichP said:

That it more than likely has a traction device in the rear, did the front do the same ??? On a normal Open diff the one tire will go one way the other tire the other way. There might also be a small metal tag on the diff. What you need to find out is what kind of LSD is back there and the only way to tell is ask the previous owner where he had it installed then go there and ask them. Second method it it was factory is to go to a dealer with the vin number and have them run it, the printout the build sheet, that will show every option that came with it. The reason you need to know is that some LSD's [Limited Slip Devices] need an additive when you change the differentials oil, most full lockers do not...
An anecdotal way to tell if it's a detroit is to do a few sharp turns in a parking lot and listen for a loud bang as the rear locks up and unlocks going around corners

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I jacked it up the front and spun one tire and the other didn't move. Do you think a dealership might be willing to open it up, identify it and refill it for fairly cheap? I have a busy schedule as of recently and don't really wanna have to fool around with it for a long time

Thanks,
Kevin

Hmmm, not sure, but maybe 92 had disco front axles possibly. I've never really looked at one before 95 because I wanted R134a A/C and not R12 system so I can't be sure. Our 89YJ had a disco front that unlocks the passenger side axle except in 4wd when a vacumn motor locks the axle so it yours does then it is possible to spin the passenger side wheel and have the drivers side do nothing.
If you have the money then sure, have the dealer do it, have them run the vin number while you are there too...

When checking the rear or front I would leave your jeep in gear/park. If you can't move the tire either way you have some sort of traction aid. If the other tires spins in the opposite direction you don't have anything. The reason I would not do this test in neutral is because there is nothing keeping the driveshaft from spinning so you could have open diffs and they could spin the same way.

I have compiled a Dana Bill of Materials listing - look for a small metal tag on the diff cover bolts or a number on the axle tube (more likely the latter is the BoM, but I can't swear to it at the moment...) and PM or email it to me and I'll look it up for you. The BoM will tell what was originally in there, and is a starting point.

I think the BoM# is on the right-hand axle tube, on the diff cover side (front of the front axle and rear of the rear axle) and if you want to pass both along, I'd be happy to look them up for you.

5-90

verrive said:

I jacked it up the front and spun one tire and the other didn't move. Do you think a dealership might be willing to open it up, identify it and refill it for fairly cheap? I have a busy schedule as of recently and don't really wanna have to fool around with it for a long time

Thanks,
Kevin

Click to expand...

pulling the diff cover requires a 1/2" socket, a wire brush, a couple paper towels, diff fluid, gasket sealer, and about 20 minutes. you would spend that long waiting at the dealer, and only learn what they tell you.

the other way to tell if you have a traction device in the rear is to pull into some gravel, stop, then stomp the accelerator. if you leave a single tire track then you have on open diff. if you leave 2 continuous parallel tire tracks then you have at least a limited slip.

Hunter

Hunter-Lynchburg said:

the other way to tell if you have a traction device in the rear is to pull into some gravel, stop, then stomp the accelerator. if you leave a single tire track then you have on open diff. if you leave 2 continuous parallel tire tracks then you have at least a limited slip.

Hunter

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Are we redneck hicks or mechanics?

Abugarcia said:

Are we redneck hicks or mechanics?

Click to expand...

Yes.