This Preliminary Information communication provides information to the technician with the axel setup information from American Axle Manufacturing. Technician should be advised that the maximum pinion shim to be used or stacked behind the pinion is 0.050?, and the minimum pinion shim is 0.020? for an 8.6 axle. The range for available pinion depth shims for the 10.5? axle is 0.006? to 0.024?. When setting the backlash it should be set between 0.003? to 0.005? on a new ring and pinion for any American Axle Manufacturing application. The ring and pinion can be reused or adjusted if the mileage is less than 500 miles, if not used for towing. Technician should be advised that a ?roller coaster? or ?hourglass? pattern on the bearings may be normal up to 10,000 miles and possibly longer. With a mis-machined housing you may get a heel pattern on both sides of the gear teeth at build up can generally be corrected with backlash adjustments. When setting up an 8.6? axle with a 5 cut gear set is to use a 0.035? pinion shim and set backlash to 0.004?. When using the newer 2 cut gear set also use a 0.035? pinion shim and still set backlash to 0.004?. To set the gear pattern use backlash to adjust the pattern heel to toe. Use the pinion shim to adjust the height of the pattern. The proper drive pinion bearing pre-load is from 15 - 30 inch pounds with new bearings. The total torque to turn after the differential case is installed should increase 5 - 10 inch pounds at the pinion. A new pinion nut must be used whenever the old one is removed. The axle shaft end play specification is 0.012? per side and the radial specification is 0.002? - 0.003?. Technician should be advised that synthetic lube can be used in all new American Axle Manufacturing axle assemblies. The new pinion seal for the 8.6? axle assembly is a two piece design.