Ford 2003 Mustang Workshop Manual page 476

11. Install the front pinion bearing and the rear axle drive pinion shaft oil slinger in the differential
housing.
12. CAUTION: Installation without the correct tool can result in early seal failure.
CAUTION: If the seal becomes misaligned during installation, remove it and install a
new one.
NOTE: Coat the rear axle drive pinion seal lips with Premium Long-Life Grease XG-1-C or
equivalent meeting Ford specification ESA-M1C75-B.
Using the special tool, install the new rear axle drive pinion seal.
13. CAUTION: Make sure the splines on the drive pinion gear stem are free of burrs. If
burrs are evident, remove them using a fine crocus cloth, work in a rotational motion.
Place a new differential drive pinion collapsible spacer on the drive pinion gear stem against the
pinion stem shoulder.
14. Install the drive pinion gear with the differential drive pinion collapsible spacer in the differential