Currently rebuilding a 3.9:1 diff. Fitted new bearings. Original shim is/was 0.136". Have also tried 0.134". Would appreciate expert advise on the markings I am getting. I've found conflicting data on the patterns and can't seem to get a marking anything like the workshop manuals I have. Current thinking is move to 0.132 shim and recheck. Am I correct to understand that changing the shim moves the mark on the narrow face of the tooth - ie - between face and flank or is it the other way between heel and toe? Photos attached show markings with 0.134 and 0.136 shim. I think the overrun side looks ok but the drive side - not so sure hence my thinking of 0.132 shim.