vehicle
2014 jeep wrangler 4dr unlimited sport model jk auto trans 4wd, i work on a ton of vehicles so i'm very familiar with vehicles, although i learn new stuff all the time

known configuration of this model, jk sports have a dana 44 rear diff with either a open or lsd rear differential (factory option) and a dana 30 front diff that is 99% open diff.

i am trying to determine if this wrangler sport has a limited slip rear differential added as factory option (for sport model) OR if it has a factory standard open rear differential.

the fca build sheet on this vin states 'anti spin rear differential'. many jk posts says 'anti spin rear diff' means limited slip rear diff, ok seems legit.

build sheet also says 'on and off road tires' from factory which i heard only wranglers with factory lsd come with 'on and off road tires'.

for my first test i went to verify by putting trans in PARK and xfer case in 2HIGH, jacking up both rear wheels and spinning driver side wheel counter clockwise (forward moving direction), with a limited slip diff (i will refer to it as LSD from now on), the passenger side wheel SHOULD rotate counter clockwise at the same time.

but it didn't. it rotated counter clock wise like a open differential. maybe someone changed out the lsd for a open? probably not. then i researched other jeeps LSD like this post (JL lsd not a JK lsd but i think jeep uses the same dana 44 lsd for both) here

https://www.jlwranglerforums.com/forum/threads/correction-fca-did-their-job.115403/page-2

this guy has the same thing happen when he was verifying his rear factory lsd. his build sheet showed a factory rear lsd but on his first test he was jacking up his rear wheels and spinning the drivers wheel, the passenger wheel rotated the OPPOSITE direction, which would behave like a OPEN differential.

he then contacted jeep thinking the factory forgot to install the rear lsd. he further stated for his first test that he left the trans and xfer case in gear when doing the test of the rear lsd.

which he states jeep said that the trans and xfer case need to be in the NEUTRAL positions to test the rear lsd. so he did a second test with BOTH in neutral and found both wheels rotated the same way when the jeep rear end was jacked up.

so for my second test i by put trans in NEUTRAL and xfer case into NEUTRAL, jacking up rear end and rotated drivers wheel counter clockwise and the passenger wheel did not rotate at all. (maybe very very slightly bumps -clock wise- 1 mm then stops).

1. at this point i have no idea what to think, if the rear diff was open i would think all gears in neural the rear wheels would rotate in OPPOSITE directions.

2. if the rear end was lsd in this, all gears in neutral situation, both wheels would rotate in the SAME direction.

any help would be appreciated.

i doubt anyone would take out a factory lsd with a open. i don't see why a build sheet would list a rear anti spin but a lsd is not in the rear end, most of the build sheets i've seen are very accurate to what's installed on the vehicle. with the caveat that some parts prior owners have have swapped out.

im not a differential tech so i'm not familiar with open/lsd/locker behaviors to understand what's going on.

i looked for a steel tag on the rear diff bolts to see if it had any numbers/letters on it as i heard it would have numbers and a 'L' for factory locker. i see no tag. i do see a stamp in the cover that says d44, which makes sense as all wrangler come with a d44 rear axle, rules out someone changed out the rear axle but doesn't help with carrier internals open or lsd.

i don't want to pull the rear diff cover yet to confirm what's inside plus i hear even with the rear diff cover off it's very hard to visually see the carrier internals to see if it's open or lsd (springs and clutch packs).

i don't want to test lsd by doing burnouts and looking for one or two skid marks and breaking parts.

 

If it’s like a normal limited slip that I have experience with then when one wheel turns the other one will also in the same direction.
‘This may help


It’s not hard to pull a diff cover, if you see clutches then of course it’s LSD, and as far as having two spin marks on the ground, maybe not, remember it’s LIMITED slip, it can still slip unless it’s a Gleason Torsion the amount of power split between the wheels isn’t as much as we would like.

 

here's another guy with the same rear diff situation on his jk, looks like worn clutch packs but at 35k it's really messed up if the clutch packs wear out at 35k miles and almost zero 4wd, off-road or trail use.

https://www.jk-forum.com/forums/stoc...-354510/page2/

here's his post stating the same differential background and behaviors im seeing and he replaced his lsd clutch plates and it fixed it.

again, if this is the case that's not cool packs wearing out with little use at 35k miles. i've never seen that before but again i don't have much expierence working on jeep rear LSDs.

 

I burnt my clutches out in a 93 Z28 in Germany in 94 by running a space saving spare for a short distance but at higher speeds, that was abuse of course but it didn’t take nearly as long as I would have thought, the different tire sizes caused continual slippage, Factory tires and factory spare.
Miata LSD’s wore prematurely and Mazda dumped the clutches pretty quickly and went with Gleason Torsion diffs.