Re: Jeep Rubicon - Extra Thick Ring/Pinion?
It's my understanding that Dana makes a 4.56 thick ring / pinion set, that can be ordered through the Jeep dealer (or, for that matter, any Dana dealer) for the Rubicon. They don't make a 4.88, but the Yukon 4.88's have been popular with no reported problems so far (one guy grenaded his locker because they used break-in oil, which is NOT recommended with the Rubicon locker... just use the normal, synthetic 75W-140 during break-in if you regear a Rubicon.)
Rubicon take off 4.10 thick cut gears are fairly cheap to find, as many Rubicon owners are re-gearing for larger tires. If all you want are 4.10 gears, I've got a set I'll sell from my rig, with 8k miles on 'em.