Originally Posted by phillybaggett
P.s. i've read 3:73s were not an option on 07 JK(at least not 2dr)
only 3:21(stock) and 4:10(optional towing package)
My understanding is the pre-2012 auto transmission JK never, ever, ever came with 3.21 gears. Only manual transmissions came with 3.21s standard prior to 2012.
This makes sense, because it would be a disaster of underpower for any fool who upgraded to the Sport S with 32" tires. They'd be turning just over 1600 RPMs or at 70 mph, which I don't think would even be enough power to keep them going on a flat highway.
But get going at 70 mph and look at the chart to confirm. Or order your build sheet to really be sure. My prediction remains that you have 3.73s or, if you have either the "off road" or "towing" package, 4.10s.