Is your Jeep feeling the effects of larger wheels and tires and a lift kit? The loss of power you're feeling is because your Jeep left the factory with ring and pinion gears installed in the axle to match the original tire size. After installing larger tires, the gear ratio needs to be changed to match the new larger tire size to regain that lost power.
When installing new ring and pinion gears, both the front and rear axle need to be done at the same time. Having different gear ratios in the front and rear axles of your Jeep will cause severe drive line damage. You'll also need a complete master install kit that includes new bearings and shims to ensure the new gears are set up properly.