Should be on the differential cover. Sometimes dirty and worn so it needs to be cleaned off. Other ways of checking, send your vin to Chrysler and they will send the build sheet. That's valid if you know it's stock.
Other ways, pop the differential cover, drain the oil, turn the wheels and count the teeth., mark one tooth to make it easier. Other way is to jack up one end, mark the driveshaft, mark a tire, turn the tire and count the revolutions of the driveshaft.
If it's the 2.5 and 5-speed he does but I think 04 was the intro for the 2.4 and 6-speed the 2.4 has more hp, so the gears can be higher.
I've got 97 5 speed and came stock with 4.10
My friends drake has 06 4 banger with 6 speed and has 4:10's as well. They may have come different with automatics. But I'm 99% sure that all the 4 bangers with manuals from 97-06 had 4.10's.
My 06 SE has 3.73 gears.... Its a manual. I was under the impression that the 03 to 04 2.4l had 4.10s with the 5 speed and the 05 to 06 had 3.73s with the 6 speed....
Ding ding ding! We have a winner!
Directly pasted from the link I put in my first post:
Axle Gear Ratios
3.07 - 1997-2006
* Standard ratio used with 6 cyl models except the Rubicon
3.55 - 1997 only
* Optional ratio used with 6 cyl
3.73 - 1998-2006
* Optional ratio used with 6 cyl manual and automatic except the Rubicon
* Standard ratio used with 6 cyl 4 speed auto
* Standard ratio used with most 4 cyl automatics * Standard ratio used with 4 cyl 6 speed
* Standard ratio used with Dana 44 rear axle except the Rubicon
4.10 / 4.11 - 1997-2006
* Standard ratio used with 4 cyl 5 speed manual
* Standard ratio used with Rubicon
4.56 - 2003-2006
* Optional ratio used with 4 cyl automatic