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Rear differential - do I have limited slip?

jonnycat

NAXJA Forum User
Location
PNW
So it's long past time to change the fluid in my rear differential, and I'm stuck on the same question that has kept me from changing this.

Do I have a limited slip differential, which needs a friction modifier in the gear lube?

This is for a stock '98 XJ SE, with 4WD (part time) and is an automatic (AW-4) with 4.0L engine.

Is there a way to determine if I have the LSD, and need a friction modifier?

Thanks!
 
You could always check the build list, that would tell you if it left the factory with an LSD. There may be a tag on the diff. You could jack up the rear end and spin one wheel, if the opposite wheel spins in the same direction, you have a non-worn-out LSD (if the LSD is worn out, it'll behave like an open diff.) Or, open up the diff and look at the carrier to see if it's an open or LSD carrier.
 
Just go ahead with the oil, while you have the cover off, take a look. Take a picture and post it if you cant figure out. Its easy to add the modifier later should you need it.
I dont run any modifier on my 8.8 LS, it works great on the trails, but i can hear it when making a right into traffic.
 
It will most likely be an 8.25" rear end, you can identify it by the flat bottom of the gear housing. Yes, there will be a sticker on the inside of the glove box cover warning you that it's LSD. Also, almost all XJ's that have a stock towing package and no ABS came with the 8.25'' limited slip. FYI, If you do have it, keep it. It's almost exactly as strong as a dana 44 if you have the higher splined shafts. Don't let your friends talk you out of it.
 
You could always check the build list, that would tell you if it left the factory with an LSD. There may be a tag on the diff. You could jack up the rear end and spin one wheel, if the opposite wheel spins in the same direction, you have a non-worn-out LSD (if the LSD is worn out, it'll behave like an open diff.) Or, open up the diff and look at the carrier to see if it's an open or LSD carrier.

Thanks Jeff. There's no tag on the diff, but just the following on the cover:

DANA
43225
283 7

And then what I assume is the date code (27 02 97). I did raise the back end and turn one wheel, and the other one spun in the opposite direction, which would indicate that I do not have LSD on this.

Just go ahead with the oil, while you have the cover off, take a look. Take a picture and post it if you cant figure out. Its easy to add the modifier later should you need it.

Great idea, thanks souske. I guess it won't kill it to drive the mile to the parts store without a modifier. I'll snap a picture when I get it cracked open; what is a telltale sign of an LSD (or a picture of one versus a non-LSD)?

My XJ has a sticker in the glove box warning me about the LS. If you have a stock diff and a sticker you have LS.

THanks scuba, I have no sticker in the glovebox, just the tire pressure thingy on the bottom of the driver's side door (it doesn't mentions the rear diff).

It will most likely be an 8.25" rear end, you can identify it by the flat bottom of the gear housing. Yes, there will be a sticker on the inside of the glove box cover warning you that it's LSD. Also, almost all XJ's that have a stock towing package and no ABS came with the 8.25'' limited slip. FYI, If you do have it, keep it. It's almost exactly as strong as a dana 44 if you have the higher splined shafts. Don't let your friends talk you out of it.

Thanks helli; this one didn't come with the towing package but it did come stock with ABS.
 
It will most likely be an 8.25" rear end..... Also, almost all XJ's that have a stock towing package and no ABS came with the 8.25'' limited slip.

I've never heard this before. I have an '01 XJ, No ABS, factory towing, 8.25" rear and also have an open carrier, no limited slip for me either. Wish I did... I wonder what the actual percentage of XJ's equipped as mentioned actually do have the LSD?? Might have to start thinking about hitting up the salvage yards and seeing if I can find one in decent condition, or if they're worth rebuilding.
 
Thanks for all the help guys. I got the fluid changed, and I didn't see any springs or a clutch, so I'm assuming this means it's standard. (pic included)

The fluid didn't look too bad for not having been changed in 6 years, but I should probably do it more often. I did the transfer case while I was waiting for the sealant to setup, and I'm glad I did because it was looking pretty brownish.

So the gear oil I put in there was the cheap stuff from WalMart (Super Tech 80w90), but now that I'm done (of course) I noticed that the FSM calls for BOTH GL5 and MIL–L–2105C specs. The stuff I used only has a GL5 spec; how concerned should I be about this?

I was planning on spraying some brake cleaner inside of the differential, but I didn't realize how much stuff was in there, and I didn't want to bork anything squirting it up in there. Do you guys use brake cleaner on yours? I'm guessing it's done on a warm day and given time to evaporate if so....

30lcpxx.jpg
 
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Also, if it came from the factory with a LSD, it also came with a FULL SIZE spare. They were burning up the LSD's with the doughnut spares.

or so I have been told & read (just not sure where)
 
That's a good point. Always run equal sized tires on a LSD or locker equipped axle.
 
Another bummer f me as I also have a full sized spare... but an Open Rear Diff. I'll have to double check it next fluid swap as I suppose it 'could be' a LSD that has worn out clutch packs, but I'm pretty sure it just open on my '01 XJ. :(
 
My 95 came with a full size spare as well, but it was simply a factory option. No LSD on it.

Even if it doesn't burn out the clutches, mismatched rear tires on an LSD may make you accelerate crooked. I got that on my old Scout with "Pow'r lok" diff, though that may have been a different setup. It locked very positively. Never did any harm, but it pulled on acceleration and then popped back when you let off the gas, like the flip side of having a bad brake.
 
Thanks for the pic xcm, they look pretty similar, but I can see the difference.

Mine also came with a full-sized spare, but I got it used from the State of Oregon, so I don't know how it came originally.
 
If it came with a LSD, you should have a factory full size spare, but just because it has a full size spare, don't mean it has LSD.

My 96 has a full size spare from the factory, but it is open in the rear as well.
 
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