Pinion Oil Seal

Tools Required:

• Companion Flange Holding Tool T78P-4851-A
• Companion Flange Remover T65L-4851-B
• Pinion Seal Replacer T79P-4676-A

Removal

Replacement of pinion oil seal only involves removal and installation of the pinion nut and circular companion flange.

 CAUTION: This operation disturbs the pinion bearing preload, and this preload must be carefully reset when assembling.

1. Raise the vehicle and install safety stands. Refer to Section 00-02. Remove the rear wheels and brake drums.

2. Make scribe marks on the driveshaft axle end yoke and axle companion flange to ensure proper position of the driveshaft during assembly. Disconnect the driveshaft from the rear axle companion flange. Remove the driveshaft from the transmission extension housing. Install an oil seal replacer tool in the transmission extension housing to prevent oil leakage.
   
   
   
   

3. Install a Nm (lb-in) torque wrench on the pinion nut. Record the torque required to maintain rotation of the pinion through several revolutions.
   
   
   
   

4. While holding circular companion flange with Companion Flange Holding Tool T78P-4851-A, remove pinion nut.
   
   
   
   

5. Clean area around the oil seal. Place a drain pan under seal, or raise front of vehicle higher than rear.

6. Mark circular companion flange in relation to pinion shaft so flange can be installed in same position.
   
   
   
   

7. Remove circular companion flange using Companion Flange Remover T65L-4851-B.
   
   
   
   

    CAUTION: Do not damage housing while removing seal.

8. Position screwdriver under flange of pinion seal and strike with hammer to wedge screwdriver blade between metal flange of pinion seal and differential housing.
   
   
   
   

9. Pry up on metal flange of pinion seal. Install gripping pliers and strike with hammer until pinion seal is removed.
   
   
   
   

Installation

 CAUTION: Installation without proper tool may result in early seal failure. If seal becomes cocked during installation, remove and replace with new seal.

1. Clean the pinion seal seat surface and install seal on Pinion Seal Replacer T79P-4676-A. Apply Premium Long-Life Grease XG-1-C (ESA-M1C75-B) or equivalent, between the rubber seal lips if seal is not pregreased.
   
   
   
   

2. Check splines on the pinion shaft to be sure they are free of burrs. If burrs are evident, remove them by using a fine crocus cloth. Working in a rotating motion, wipe the pinion clean.

3. Install pinion seal in carrier.
   
   
   
   

   NOTE: Check circular companion flange for burrs. Remove burrs as necessary.

4. Apply a small amount of Rear Axle Lubricant to circular companion flange splines.

5. Align mark on circular companion flange with mark on the pinion shaft. Install flange.

6. Install a new pinion nut on pinion shaft (apply a small amount of lubricant on the washer side of nut).

7. Hold the circular companion flange with Companion Flange Holding Tool T78P-4851-A while tightening the nut.
   
   
   
   

8. Rotate pinion occasionally to ensure proper bearing seating. Take frequent pinion bearing torque preload readings while tightening, until the original recorded preload reading is obtained.

    CAUTION: The circular companion flange must never be hammered on, or assembled with power tools.

9. If the original recorded preload is less than specification, tighten to specification. If the preload is higher than specification, tighten to original reading as recorded.

   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.

10. Remove oil seal replacer tool from the transmission extension housing. Install the front end of the driveshaft on the transmission output shaft.

11. Connect the rear end of the driveshaft to the axle companion flange, aligning the scribe marks on the driveshaft and circular companion flange. Tighten the four bolts to 95-130 Nm (70-95 lb-ft).

     CAUTION: Overfilling axles can cause axle leakage.

12. Fill axle with lubricant until fluid level is within 6-14mm (1/4 - 9/16 inch) below bottom of filler hole with the axle in operating position. Add four ounces of Additive Friction Modifier C8AZ-19B564-A (EST-M2C118-A) or equivalent for Traction-Lok axles. Refer to Specifications. Install oil filler plug. Tighten to 20-41 Nm (15-30 lb-ft).

13. Ensure axle vent is not plugged with debris.