FORD 2001 Crown Victoria - Manual (Page 222)

5 Rear axles are considered lubricated for life when the vehicle is used for
normal service. See your scheduled maintenance guide for Severe Duty
requirements.
Traction-Lok axles use 1.6-1.8L (3.50-3.75 pints) of rear axle lubricant.
Add 118 ml (4 oz.) of Additive Friction Modifier C8AZ-19B546-A or
equivalent meeting Ford specification EST-M2C118–A for complete refill
of Traction-Lok rear axle.
Service refill capacities are determined by filling the rear axle 6 mm to
14 mm (1/4 inch to 9/16 inch) below the bottom of the filler hole.
Capacities and specifications
222