Jerry;
My TJ maintains 65 mph effortlessly at considerably less than WOT, UNTIL I start up the mountain (7% grade). Then, I must downshift, as 5th. gear is the only way up. The TJ 6th. gear is less than a 1-1 ratio and only good on level or slight upgrades. Btw, when I installed the 31s, the rpms, at 60mph, dropped to about 1900 rpms,depending on the grade. No change in the gas mileage though. Now I'm wondering if I should consider that 3:73 axle.
Btw, this reply is also to freedom in 4low and Chris.