ADJUSTABLE Modern Drive Shaft Pinion Bearing Assembly, with open spool. These assembly is similar to the 2587PB2 kit, however, this kit also includes a full shim set that allows an easy yet precise control of ring and pinion gear mesh of 0.0005"! Modern roller bearing reduces drag. This kit replaces parts #2587, 2589B, and 2596. Installs in minutes - no machining required. No lost "show points" - invisible after installation! Uses a tapered lower roller bearing and a sealed upper bearing which prevents drive shaft housing debris from entering pinion bearing or differential gear. Eliminates all drive shaft end play, allowing you to use roller bearing part #2581RB without need for precision U-joint end play setting. Complete instructions provided to make a breeze even for non-experienced person.