2006 Honda TRX680 Rincon Factory Service Manual, Page 462Get this manual
FRONT DRIVING MECHANISM Remove the oil filler capRotate the ring gear several times in both directions of rotationCheck the gear tooth contact pattern through the oil filler holeThe pattern is indicated by the Prussian Blue applied to the pinionContact is normal if the Prussian Blue is transferred to the approximate center of each tooth, but slightly to the heel side and to the flank sideIf the patterns are not correct, remove and change the pinion shim with one of an alternate thicknessReplace the pinion shim with thicker one if the contact pattern is too high, toward the faceTOO HIGH: PINION SHIM FACE NORMAL: HEEL TOE FACE
FLANK FLANK Drive side Coast side