Mazda Trucks 1994-1998 Repair Guide

Pinion Seal


This service procedure disturbs the pinion bearing preload and this preload must be carefully reset when assembling.

  1. Raise the vehicle and support it safely.
  3. Drain the differential oil.
  5. Remove the wheels and the brake rotors.
  7. Mark the driveshaft and the axle companion flange so the driveshaft can be reinstalled in the same position. Remove the driveshaft.
  9. Using an inch pound torque wrench on the pinion nut, record the torque required to maintain rotation of the pinion through several revolutions.
  11. While holding the companion flange with a suitable tool, remove the pinion nut. Mark the companion flange in relation to the pinion shaft so the flange can be reinstalled in the same position.
  13. Using a 3-jawed puller tool or equivalent, remove the rear axle companion flange. Use a small prybar to remove the seal from the carrier.

To install:
  1. Make sure the splines of the pinion shaft are free of burrs.
  3. Apply grease to the lips of the pinion seal and install, using a seal installation tool.
  5. Check the seal surface of the companion flange for scratches, nicks or a groove. Replace the companion flange, as necessary. Apply a small amount of lubricant to the splines. Align the mark on the flange with the mark on the pinion shaft and install the companion flange.

The companion flange must never be hammered on or installed with power tools.

  1. Install a new nut on the pinion shaft. Hold the companion flange with a suitable tool while tightening the nut.
  3. Tighten the pinion nut, rotating the pinion occasionally to ensure proper bearing seating. Take frequent pinion bearing torque preload readings until the original recorded preload reading is obtained.

Under no circumstances should the pinion nut be backed off to reduce preload. If reduced preload is required, a new collapsible pinion spacer and pinion nut must be installed.

  1. Install the driveshaft and add the correct amount and type of differential fluid to the carrier. Lower the vehicle.