When you "re-gear" an axle, you're bascially changing the ring and pinion gears to get the desired ratio. Since the axle is totally diassembled in most cases, it's a good time to install a traction aide for better grip offroad. It's also a good time to replace bearings and seals, especially if the old ones are the originals from 20 years ago, show some wear, or are leaking gear oil. The basic r & p kit costs about $140, and the master install kits have all of the bearings and seals you need to replace. You can re-use the OEM ring gear carrier in some cases, but for the front if you go from 3.92 gears or lower (like 3.55 or 3.08), you'll need a new carrier for higher ratios, like 4.10's or 4.56's. Any of the gear vendors will give you all the tech info you need and answer any questions about the gear swap. You often need shims or thin washers to "set" the gears in proper alignment or "mesh". Otherwise, they will wear really fast or flat out break. IF a vendor does not answer your questions, by all means go to someone who will!!! I bought my gears from 4WheelParts. They are Genuine brand gears with a lifetime warranty. There are many vendors of other brands with similar warranties, such as Yukon gears. Do alot of searching beforehand, as it will help to decide what you want to use the new gear ratio for, be it ******** offroad, daily driving, or a mixture. JSM84