3.07 are on the other side of the sweet spot for mpgs. I got better mpgs when I bumped up to 3.55s. :thumbsup: but, as with everything else in the Jeep world, individual results may vary.
and just to double check, are you sure that's a crack in the t-case rather than a casting flaw? I had what I thought was a crack in a trans a while back but it turned out that it just looked like a crack. :yes: