Jeff Daniel's Axle Upgrades

General Maintenance

Gearing

Lockers

Chromoly Shafts

Axle Tube Seals

Gussets

Inner Tubes

Trusses

Brake Upgrades

Differential Covers

Skid Plates

Complete Swaps

Gearing

Jeep has used many gear ratios throughout its history, everything from a 2.72 CJ to the 4.11 Rubicon. What does it all mean? The gear ratio is determined by the tooth count on your ring and pinion, the higher ratio (lower number) is a good highway gear, it will allow you to run higher speeds at a lower RPMs therefore better fuel economy and lower engine temperature. A high gear is not good for towing, off roading, or around town driving. A lower gear (higher number) is required to run larger tires, better for off road and for towing. You will sacrifice MPGs on the highway but gain some around town. 
Your final drive ratio is effected by your transmission ratio, transfer case ratio, axle gear ratio, and tire size. When you add a larger tire to a vehicle you are ultimately lowering the final drive ratio which is why it is important to have proper gearing before modifying your Jeep.

A proper gear swap can take 6-8 hours per axle. It is a delicate procedure that requires patience and knowledge, the basics are simple mechanics but if backlash and pinion depth are not properly set your regear will have to be regeared again in a year. Beware of shops that say they can do both axles in a day - trust us on this, we see plenty of 'price shoppers' that wasted a lot of money and cost themselves a lot more to repair the damage. You wouldn't let Jeff Daniel's pull out a molar, don't let an amateur regear your axles. 
Here is a great article on the subject; fourwheeler 
Pictured below is a ring and pinion (gear set) and a Master Overall kit (required when regearing an axle).