Are you replacing just the bearings, or is a new ring & pinion on the agenda? A simple bearing swap just involves pressing the old bearing cones off the pinion gear and the ring gear carrier, driving the cups out of the front and rear pinion positions in the housing, and reassembling with the same shims everywhere. He will need a new "crush sleeve" to put between the front and rear pinion bearings, and do the pinion preload setting procedure.
If new gears are installed, it will be necessary to adjust the pinion depth for the proper tooth contact pattern, and possibly change the thickness of the carrier bearing spacer washers to set the backlash. An "installation kit" that is sold by the same people who sell the gears should have all the shims, gaskets, seals, and bearings necessary to do the job properly. The necessary clearances and bearing preload specifications will be available in the chassis service manual for your truck.
It sounds like your guy doesn't have the experience necessary to do rear axle work, as there's only one chance to get it right.
Jerry
Last edited by Hotrod Lincoln; 07/13/2008 8:54 PM.
