2001 Mercury Mariner 50-60HP Factory Service Manual, Page 441Get this manual
NON-BIGFOOT GEAR HOUSING
Pinion Gear Location and Forward Gear Backlash
DETERMINING PINION GEAR LOCATION NOTE: Read entire procedure before attempting any change in shim thicknessIMPORTANT: Forward gear assembly pilots the end of the pinion gage and must be installed in gear housing when checking pinion gear depthWithout it an inaccurate measurement will be obtained1Clean the gear housing bearing carrier shoulder and diameter2Position gear housing upright (driveshaft vertical)Install Bearing Preload Tool (9114311A2) in sequence shown