Ford F77Z-7052-AA Oil Seal Assembly

Raise the vehicle and support it securely on jack stands, ensuring that if equipped with Automatic Ride Control (ARC), the air suspension switch is turned to the OFF position to prevent damage to the system components. Place a drain pan under the extension housing, as some transmission lubricant may drain out when the driveshaft slip joint is withdrawn. Remove the driveshaft. Use a seal removal tool to take out the oil seal from the end of the extension housing, being cautious not to damage the housing if using a thin blade screwdriver or chisel instead. Inspect the sealing surface on the driveshaft slip joint for any scoring or burrs that could damage the new oil seal, and replace the yoke if it is damaged. Check the extension housing bore for burrs and remove them with emery cloth or medium grit wet-and-dry sandpaper, then clean the bore with a cloth dipped in solvent. Apply silicone sealant to the outside diameter of the oil seal and multipurpose grease to the seal lip. Using a seal driver, large socket, or section of pipe, install a new oil seal, ensuring it is completely seated and square to the housing. Install the driveshaft, lower the vehicle, and check the transmission lubricant level, topping up if necessary.

On later models, a snap-ring holds the front driveshaft yoke on the transfer case. Replacing the seal at the front yoke requires removal of the transfer case from the vehicle and some disassembly to access the snap-ring.

Install the new rubber seal, steel washer, and nut. Tighten the nut to the specified torque.

Raise the vehicle and support it securely on Jackstands.

Inspect the oil seal contact surface on the universal joint yoke for scoring or burrs that may damage the new oil seal. If the yoke is damaged in any way, replace it.

Remove them with emery cloth or medium grit wet-and-dry sandpaper, and use a clean cloth dipped in solvent to remove any sanding residue from the counterbore.