just installed a 4.10 gearset in a GM 10bolt axle, trans am for a friend, backlash set at .007 and contact pattern smooth and across the gear tooth face about 3/16in up from bottom of tooth,with 2lbs load on pinion after torquing nut to 90ftlbs and new sleeve, with stock shim the pattern was on the heel of the gear tooth, so i put 4 of the thinner shims (.040)+stock shim to get the pattern centered, so then i had to keep 1 stock carrier shim and 1 thick and 3 thin shim from kit on right side and 2 thick shim from kit and remove stock shim altogether. everything went together well but test drive has gear noise like a axle in a 1 1/4 ton truck. searched the site and it seems this is a common theme with richmond gears, is there any fix, can the contact pattern be moved in or out from center to lessin the noise or do you have to live with it?