Editing Drum brake (section)

==As a driveshaft parking/emergency brake==
{{Further|Transmission brake}}
Drum brakes have also been built [[transmission brake|onto the transmission's driveshaft]] as parking brakes (e.g., Chryslers through 1962). This provides the advantage that it is completely independent of the service brakes—but suffers a severe disadvantage in that, when used with a bumper jack (common in that era) on the rear, and without proper wheel blocks, the differential's action can allow the vehicle to roll off the jack.

Land Rover have used a drum brake on the gearbox output shaft for over fifty years.  The advantage is that all four wheels can be braked with the parking brake.