Steve94

Bought a used 2011 jeep jk sport 2door couple months back.

3.21 gearing (maybe)?
D44 R
D30 F


Let me begin by saying this whole journey to figure out what this jeep is equipped with has been a complete struggle. Prior to purchase i asked the used dealer what axel ratio it had and he said, "3.73 confirmed by dealer". whatever, so i went ahead and got it.

But when i had a Chrysler dealer run the VIN he said it was 3.21. Is the used dealer wrong? Wouldn't he have to run the VIN also to give me the ratio? I'm getting two different answers here from two different dealers. is there a way to figure out on my own??

I know that if you were to buy a trailer package from factory it automatically came with 3.73 instead of 3.21. My jeep does have a receiver/hitch. But i asked the used dealer if the original owner had it put on from the factory, or if he put it on himself. and i never got a straight answer.

I did some research on this site and found out if you jack up the rear end and spin a tire one revolution clockwise WHILE watching the driveshaft you can come up with a ratio. I got 2.5 turns? Not even sure thats absolutely correct.

Another issue, do i have locking diffs? i didnt bother asking a dealer, so i did a little test on my own. I drove into a parking lot filled with left over sand from the winter and did a tiny burnout, got out and saw 2 rear tire marks, does this mean i have lockers? Tried it in 4x4 also, then when i try to turn left or right in 4x4 it wants to play hop skotch.

So question one: What axel ratio do i have? How can i find out?
Question 2: Do i have locking differentials or Command Trac?


In the near future i want to get 35s and a 4"lift before i swap out to 4.88

ronjenx

If you jack up one tire, you must turn it 2 turns to get a direct reading off the drive shaft.
If you jack up 2 tires on the axle and spin them both, you must be absolutely sure they both turn exactly one turn.

Here is the procedure, if you want to try it again.

Place a chock in front of and in back of the right rear tire.
Put the transmission in neutral.
Emergency brake off.
Jack the left rear tire off the ground.
Put a jack stand under the frame, just in case the jack fails (had to add this).
Put an index mark on the rearmost end of the drive shaft, visible from the left rear wheel.
Put an index mark on the left rear tire at the 6 o'clock position.
Rotate the left rear tire 2 complete revolutionswhile counting how many times the index mark on the drive shaft passes its original position.
That number will be your axle ratio.
Remove jackstand and lower jack.
Put transmission in gear and/or apply emergency brake.
Remove chocks.

If you have limited slip, jack up both rear wheels and rotate one revolution, making sure both tires rotate equally.

If the drive shaft rotated almost 3¼ turns, you have 3.21
If the drive shaft rotated almost 3¾ turns, you have 3.73
If the drive shaft rotated a little over 4 turns, you have 4.10
If the drive shaft rotated 4½ turns, you have 4.56
If the drive shaft rotated a little under 5 turns, you have 4.88
If the drive shaft rotated a little over 5 turns, you have 5.13

Nwapache

Easy answer for you.... Run the vin, it's going to tell you how it was built.

Wads13

Go to Jeep.com, sign up to be a "registered Jeep owner", then insert your VIN... There you can see all of the information regarding your Jeep. Please remember this information is for the stock applications, it obviously will not tell you about the aftermarket upgrades, etc...

mSchvOus

what he said

ronjenx

The OP obviously wants to know for sure. Getting the build sheet will not answer his question, as he bought the Jeep used, and is already getting two different answers regarding his axle ratio.