Pinion oil seal — replacement Ford F150
Note: This procedure applies to the front and rear pinion oil seals.
1. Loosen the wheel lug nuts. Raise the front (for front differential) or rear (for rear differential) of the vehicle and support it securely on jackstands. Block the opposite set of wheels to keep the vehicle from rolling off the stands. Remove the wheels.
2. Disconnect the driveshaft from the differential pinion flange and support it out of the way with a piece of wire or rope (see Driveshaft(s) – removal and installation).
Use an inch-pound torque wrench to check the torque necessary to rotate the pinion shaft flange before removing the nut
3. Rotate the pinion a few times using a beam-type or dial-type inch-pound torque wrench to check the torque required to rotate the pinion . Record it for use later.
Mark the relative positions of the pinion and
4. Mark the relationship of the pinion flange to the shaft. It’s also a good idea to count the amount of exposed threads as a reference when reinstalling the pinon flange .
If you don’t have a special flange holding tool to hold the pinion flange while loosening and backing off the pinion flange locknut, use a screwdriver inserted through a hole in the flange and jammed against the top of the reinforcing rib on the differential carrier
5. A special tool (available at most auto parts stores) or a chain wrench can be used to keep the companion flange from moving while the self-locking pinion nut is loosened. A screwdriver or long punch inserted through one of the holes in the flange can also be used to immobilize the flange.
6. Remove the pinion nut.
If the pinion flange is difficult to remove, pull it off with a two- or three-jaw puller
7. Withdraw the flange. It may be necessary to use a two-jaw puller engaged behind the flange to draw it off. Do not attempt to pry or hammer behind the flange or hammer on the end of the pinion shaft .
Pry out the old pinion seal with a seal removal tool
8. Pry out the old seal and discard it.
Lubricate the lips of the new pinion seal and seat it squarely in the bore, then drive it into the carrier with a seal driver or a large socket
9. Lubricate the lips of the new seal and fill the space between the seal lips with wheel bearing grease, then tap it evenly into position with a seal installation tool or a large socket . Make sure it enters the housing squarely and is tapped in to its full depth.
10. Install the pinion flange, lining up the marks made in Step 4. If necessary, tighten the pinion nut to draw the flange into place. Do not try to hammer the flange into position.
11. Apply a bead of RTV sealant to the ends of the splines visible in the center of the flange so oil will be sealed in.
12. Install the washer and a new pinion nut. Tighten a little at a time until the drag recorded previously is reached. As a check only, count the number of exposed threads showing just in case a burr on a thread is causing a false reading of the torque value.
13. Measure the torque required to rotate the pinion and tighten the nut in small increments (no more than 5 ft-lbs) until it matches the figure recorded in Step 3. To compensate for the drag of the new oil seal, the nut should be tightened a little more until the rotational torque of the pinion exceeds the earlier recording by 3 in-lbs. for the rear pinion and no more than 5 in-lbs. for the front pinion on 4WD drive vehicles.
14. Reinstall all components removed previously by reversing the removal Steps, tightening all fasteners to their specified torque values. Check the fluid level in the differential and adjust as needed.