Seir

You are correct, they all start with a 4.10; didn't know it was a Rubicon

Keith615

No, that is incorrect. 2008 Rubicons came with 4.10 in the US. That is the only way you could get 4.10s from the factory though.

ronjenx

If you want to know for sure, and remove all doubt, do this:

Chock the right rear tire, fore and aft.
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 aft 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 revolutions while 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.

999666

Think a possible mis-calculation.

Mine with 3:73 gears is @ 2500 rpm in 5th at 60 MPH.

OP looks like you have 3:73 gears.