I just bought a 2010 Unlimited, I believe the stock gears a 3.21 (correct me if that doesnt sound right) but i think thats what the window sticker said. Its an automatic if that helps. I've been reading all over this forum about tires and what will fit with no lift kit. I'm looking at going to 31" tires maybe a bit bigger, simular to what the rubicon comes with stock. But will that have any effect with the 3.21 gears? Another note to add, This is my daily driver and only sees dirt trails/ old fire roads and the ocassional mud holes a few time a year when I go Rock climbing at Red River Gorge Kentucky. Thats me rock climbing not the Jeep!