Ford 2006 Crown Victoria User Manual page 166

Tires, Wheels and Loading
• Maximum distance is 50 miles (80 km)
If a distance of 50 miles (80 km) or a speed of 35 mph (56 km/h) must
be exceeded, you must disconnect the driveshaft. Ford Motor Company
recommends the driveshaft be removed/installed only by a qualified
technician at an authorized dealer. See your authorized dealer for
driveshaft removal/installation.
Improper removal/installation of the driveshaft can cause
transmission fluid loss, damage to the driveshaft and internal
transmission components.
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