Rear pinion seal replacement

If you are talking the rear pinion seal, it isn't too bad at all. You just have to drop the drive shaft, remove the pinion nut and pull the pinion, then knock out the old seal and hammer in the new one. Going back together is just the reverse but you have to torque the pinion nut to the specified setting. As long as you are not removing the pinion gear you do not need to worry about setting the rear end up or worry about the crush sleeve.

This is not really a job for a novice. You will have to remove the rear drive shaft from the pinion, remove the pinion nut and the pinion itself, then remove the seal and replace with a new one. The tricky part is getting the pinion replaces and getting the correct torque setting without changing the pinion depth and compressing the crush sleeve more than spec.

what about it?

conventional axle or limited slip? Get axle code off door sticker.

SECTION 205-02: Rear Drive Axle/Differential - Ford 8.8-Inch Ring Gear 1998 Explorer/Mountaineer Workshop Manual
IN-VEHICLE REPAIR Rear Wheel Bearing and Axle Shaft Oil Seal -4.0L SOHC and 4.0L EI, Conventional
Special Tool(s) Axle Seal Replacer
T83T-1175-A Axle Wheel Bearing Puller
T83T-1225-A Axle Wheel Bearing Replacer
T83T-1225-B Driver Handle
T80T-4000-W Impact Slide Hammer
T50T-100-A
Removal

1. Remove the axle shaft; refer to Axle Shaft in this section.

Axle Shaft Removal

1. CAUTION: Do not use heat to loosen a seized lug nut. Heat can damage the wheel (1007) and the rear wheel bearings (1225).
   Loosen the lug nuts (1012).
   1. Remove the center cap.
   1. With the weight of the vehicle on the wheels, loosen the lug nuts.

1. Raise and support the vehicle.

1. Remove the wheel and tire assembly.
   1. Remove the lug nuts.
   1. Remove the wheel and tire assembly.

1. Remove the axle housing cover (4033).
   1. Loosen the axle housing cover bolts (4346) and drain the rear axle (4001).
   1. Remove the axle housing cover bolts.
   1. Remove the axle housing cover.

1. Remove the rear disc brake rotors (2C026); refer to Section 206-04 .

1. CAUTION: Once the differential pinion shaft (4211) has been removed, turning the differential case (4204) or an axle shaft (4234) will cause the differential pinion gears (4215) to fall out of the assembly. This could result in chipped or damaged components.
   Remove the differential pinion shaft.
   1. Remove the differential pinion shaft lock bolt.
   1. Remove the differential pinion shaft.

1. CAUTION: Do not damage the rubber O-rings in the U-washer grooves.
   Remove the U-washers (4N237).
   1. Push the axle shafts inboard.
   1. Remove the U-washers.

1. Reinstall the differential pinion shaft.
   1. Install the differential pinion shaft.
   1. Install the differential pinion shaft lock bolt finger-tight.

1. CAUTION: Do not damage the inner wheel bearing oil seal (1177).
   Remove the two axle shafts.

Installation

1. Lubricate the lip of the inner wheel bearing oil seal.
   • Use Premium Long-Life Grease XG-1-C or equivalent meeting Ford specification ESA-M1C75-B.

1. CAUTION: Once the differential pinion shaft has been removed, turning the differential case or an axle shaft will cause the differential pinion gears to fall out of the assembly. This could result in chipped or damaged components.
   Remove the differential pinion shaft.
   1. Remove the differential pinion shaft lock bolt.
   1. Remove the differential pinion shaft.

1. CAUTION: Do not damage the inner wheel bearing oil seal.
   Install the two axle shafts.

1. CAUTION: Do not damage the rubber O-rings in the U-washer grooves.
   Install the U-washers.
   1. Position the two U-washers on the button end of the axle shafts.
   1. Pull the axle shafts outward.

1. Install the differential pinion shaft.
   1. Align the hole in the differential pinion shaft with the differential pinion shaft lock bolt hole.
   1. Install the differential pinion shaft lock bolt.

1. Install the rear disc brake rotors; refer to Section 206-04 .

1. Install the axle housing cover and fill the rear axle housing (4010) with 2.4 liters (5.5 pints) of specified lubricant; refer to Axle Housing Cover in this section.

1. WARNING: Always remove any corrosion, dirt or foreign material that may be present on the mounting surfaces of the wheel or the surface of the wheel hub or rear disc brake rotor that contacts the wheel. Installing wheels without proper metal-to-metal contact at the wheel mounting surfaces can cause the lug nut to loosen and the wheel to come off while the vehicle is in motion, causing loss of control.
   Clean the wheel hub and mounting surfaces.

1. Install the tire and wheel assembly.
   1. Position the tire and wheel assembly.
   1. Install the lug nuts and lower the vehicle.
   1. Tighten the lug nuts.
   1. Install the center cap.

1. CAUTION: Never remove the axle shaft oil seal by itself. Always remove the rear wheel bearing and the axle shaft oil seal at the same time.
   NOTE: If the axle shaft oil seal is leaking, the axle housing vent may be plugged with debris.
   Use Impact Slide Hammer and Axle Wheel Bearing Puller to remove the rear wheel bearing and the axle shaft oil seal.

Installation

1. Lubricate the new rear wheel bearing.
   1. Use Thermally Stable Rear Axle Lubricant XY-80W90-QL or equivalent meeting Ford specification WSP-M2C197-A.

1. Use Axle Wheel Bearing Replacer with Driver Handle to install the rear wheel bearing.

1. Lubricate the lip of the new axle shaft oil seal.
   • Use Premium Long-Life Grease XG-1-C or equivalent meeting Ford specification ESA-M1C75-B.

1. Use Axle Seal Replacer with Driver Handle to install the axle shaft oil seal.

1. Install the axle shaft; refer to Axle Shaft in this section.

go to the web link below, it is a jeep owner forum, it explains how to do the job with pictures.
http://www.cherokeeforum.com/f51/how-replace-rear-pinion-seal-5869/

Sounds like the original wear pattern of the ring and pinion was disturbed when the pinion was tightened too much. Once a wear pattern is set in the gears you can't really change it. It might be the ring and pinion wearing that you are hearing and not a bearing at all. It's not the worst thing in the world but will cause the ring and pinion to wear improperly and is annoying. Differential work needs to be done by someone that really knows their stuff to avoid these little problems.

Depending on what part of the pinion you want to replace the seal,bearing,or pinion itself.Either way if you are not familiar with the rear end you could do a lot of damage and it could cost you more money.There are also certain tools that you will need.I have seen people ruin rear ends just replacing the pinion seal.Which is a fairly easy job.If you are replacing the pinion shaft itself then the axles and the complete rear carrier has to come out.Then it has to be set up.Hope this helps.Good luck.

You probably have the 9 inch differential. If it is a rear wheel seal remove the tire and wheel assembly. Be sure to use a jack stand so you don't have the vehicle fall on you. Remove the 4 retaining bolts that hold the backing plate onto the housing. Pull the axle from the axle tube. It may be stubborn at removal. If it is the pinion seal remove the drive line. Remove the pinion nut that rests inside the yoke. Try to use an impact tool for easy removal. Once the nut is off the yoke willcome off. You may need a puller to help in removal. One the yoke is off remove the pinion shaft seal. Replace with a new seal. install the yoke and the washer and then the pinion nut. Re-torque the pinion nut to 150 foot pounds.

Axle Shaft Removal

1. Raise and support the vehicle. For additional information, refer to Section 100-02 .

1. Remove the wheel and tire assembly. For additional information, refer to Section 204-04 .

1. Remove the differential housing cover (4033).
   1. Loosen the bolts and drain the lubricant from the rear axle housing (4010).
   1. Remove the bolts.
   1. Remove the differential housing cover.

Remove the rear brake disc (2C026). For additional information, refer to Section 206-04 .

1. CAUTION: Turning the differential case (4204) or an axle shaft (4234) with the differential pinion shaft (4211) removed will cause the differential pinion gears (4215) to fall out of the assembly and damage the components.
   Remove the differential pinion shaft.
   1. Remove the differential pinion shaft lock bolt.
   1. Remove the differential pinion shaft.
2. CAUTION: Do not damage the rubber O-ring in the U-washer groove.
3. Remove the U-washer (4N237).
4. Push the axle shaft inboard.
5. Remove the U-washer.

Reinstall the differential pinion shaft.

1. Install the differential pinion shaft.
2. Install the differential pinion shaft lock bolt finger-tight.
3. CAUTION: Do not damage the wheel bearing oil seal (1177).
   Remove the axle shaft.

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Seal Removal

1. Remove the axle shaft (4334). For additional information, refer to Axle Shaft in this section.

1. CAUTION: Never remove the wheel bearing oil seal (1177) by itself. Always remove the rear wheel bearing (1225) and the inner wheel bearing oil seal at the same time.
   NOTE: If the wheel bearing oil seal is leaking, the axle housing vent may be plugged with foreign material.
   Using the special tools, remove the rear wheel bearing and wheel bearing oil seal together.

Installation

1. Lubricate the new rear wheel bearing.
   • For 4.0L SOHC and 4.0L EI with limited slip rear axles and 5.0L vehicles, use SAE 75W-140 High Performance Rear Axle Lubricant F1TZ-19580-B or equivalent meeting Ford specification WSL-M2C192-A.
   • For 4.0L SOHC and 4.0L EI with conventional rear axles, use SAE 80W-90 Premium Rear Axle Lubricant XY-80W90-QL or equivalent meeting Ford specification WSP-M2C197-A.

1. Using the special tools, install the rear wheel bearing.

1. Lubricate the lip of the new wheel bearing oil seal.
   • Use Premium Long-Life Grease XG-1-C or equivalent meeting Ford specification ESA-M1C75-B.

1. Using the special tools, install the wheel bearing oil seal.

1. Install the axle shaft. For additional information, refer to Axle Shaft in this section.

Here is a guide on how to change the rear seal and bearings on a ford mustang
http://fhmotorsports.blogspot.com/2013/07/how-to-change-rear-axlewheel-seal-and.html

check your rear diff vent if pluged clean it out and clean up the pinion seal.sometimes if the leak is caused by pluged vent and has not been leaking long once vent is clean sometimes the leak will stop.there is not a specific torque amount because it is rotational torque(how hard to turn pinion).there is a crush sleve on the pinion and if torqued too tight or too loose brg preload will be wrong and brg damage could result.mark and remove drive shaft.remove rear wheels,brakes,axles.so when turning pinion you dont have any drag from brakes or axles.mark the position of the yoke on the pinion.remove yoke,replace seal,reinstall yoke be sure to replace pinion nut.tighten nut until it takes the exact same amount of force to turn pinion as before taking original pinion nut off.hope this helps.