Front Differential Master Overhaul Kit (YKD30-SUP) by Yukon Gear and Axle. With Timken Bearings and Races Along With High Quality Seals and Small Parts. Building a strong rearend requires strong parts. Yukon Gear and Axle bearing, installation, and overhaul kits use Timken bearings for long bearing life and strength. Yukon Gear and Axle stocks Timken bearings separately as well as in five different levels of kits - from bearings and seals only to Yukon Gear and Axle's complete master overhaul kits.