- Parking pawl
A parking pawl is a device fitted to a car's
automatic transmissionthat locks up the transmission. It is engaged when the shift selector is placed in the Park position, which is always the first position (topmost on a column shift, frontmost on a floor shift) in all cars sold in the United Statessince 1965(when the order was standardised by the SAE) and in most other vehicles worldwide.
The parking pawl locks the transmission's "output shaft" to the transmission casing by engaging a "pawl" (a pin) that engages in a notched wheel on the shaft, stopping it (and thus the driven wheels) from turning.
Most manufacturers and mechanics do not recommend using the transmission's parking pawl as the sole means of securing a parked vehicle, instead recommending it should be engaged after first applying the vehicle's
parking brake. Constant use of the parking pawl only, especially when parking on a steep incline, means that driveline components are kept constantly under stress, and can cause wear and eventual failure of the parking pawl or transmission linkage. The pawl might also fail or break if the vehicle is pushed with sufficient force, if the parking brake is not firmly engaged. Replacement can be an expensive operation since it generally requires removing the transmission from the car.
It is also not recommended to use the parking pawl to stop a vehicle in motion. The pawl mechanism is not strong enough to stop a vehicle in motion or may not engage at all. Under that much stress, the pawl may break off in the transmission, leading to costly repairs.
Wikimedia Foundation. 2010.
Look at other dictionaries:
pawl —  A bar, pin, or stud that can be moved, pivoted, or slid into engagement with teeth cut on another part, such as the parking pawl on the automatic transmission that can be slid into contact with teeth on another part to lock the rear wheels.… … Dictionary of automotive terms
parking lock — (PL) A lock gear and pawl that lock the transmission mechanically … Dictionary of automotive terms
Automatic transmission — An automatic transmission (commonly AT or Auto ) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, freeing the driver from having to shift gears manually. Similar but larger devices are also used for heavy… … Wikipedia
Drum brake — A drum brake with the drum removed as used on the rear wheel of a car or truck. Note that in this installation, a cable operated parking brake uses the service shoes … Wikipedia
Hydramatic — (also known as Hydra Matic) was an automatic transmission developed by both General Motors s Cadillac and Oldsmobile divisions. Introduced for the 1940 model year, the Hydramatic was the first fully automatic mass produced transmission developed… … Wikipedia
TorqueFlite — Manufacturer Chrysler Corporation Production 1956– Predecessor PowerFlite Class 3 or 4 speed automatic TorqueFlite (also seen as Torqueflite) is the trademarked name of Chrysler Corporation s automatic trans … Wikipedia
Hand brake — In cars, the hand brake (also known as the emergency brake, e brake, park brake, slide stick or parking brake) is a latching brake usually used to keep the car stationary. Automobile e brakes usually consist of a cable (usually adjustable for… … Wikipedia
Disc brake — Close up of a disc brake on a car On automobiles, disc brakes are often located with … Wikipedia
Steering — For other uses, see Steering (disambiguation). Part of car steering mechanism: tie rod, steering arm, king pin axis (using ball joints). Steering is the term applied to the collection of components, linkages, etc. which will allow a vessel (ship … Wikipedia
Automobile — For the magazine, see Automobile Magazine. Car and Cars redirect here. For other uses, see Car (disambiguation). Automobile … Wikipedia