What Causes a Transmission to Stick in Park?by Dave Hendrickson
There’s nothing like a transmission getting stuck in "Park" to trigger worries about costly repairs. Sometimes, those fears are justified, but not always – various minor conditions can cause a sticky transmission and several require no repair at all. Make sure you or your mechanic have correctly diagnosed the problem before you give the OK for a costly rebuild of your transmission.
Brake Not Depressed
On most cars, the brake pedal must be fully depressed before the transmission can be shifted out of park. An obstruction under the brake pedal, such as a floor mat, may prevent the brake pedal from being fully depressed.
Short in Brake Electrical System
Another built-in safety feature in many cars is that the brake lights are interfaced to the electrical circuit that locks the shift lever. If you’re stuck in park, check your brake lights. If they don’t work, there may be a short or a blown fuse. Repairing this minor problem will restore your shift lever to working order and allow you to shift out of park.
Pressure from Sitting on a Hill
If a car is parked on a hill without the parking brake set, it can roll slightly forward or backward. That puts pressure on the pawl -- the pin attached to the transmission that keeps the car from rolling. Repeatedly putting pressure on the pawl can wear it down and eventually it will need to be replaced. If you frequently park on inclines, get in the habit of setting the parking brake.
Faulty Shift Lever Button
If the button on the shift lever does not engage, electric current will not flow to the shift-lock solenoid. Without power, the solenoid cannot move the shift-lock plate. As the name suggests, the shift-lock plate prevents the car from shifting out of park.
Inoperative Shift Lock Solenoid
If power is flowing to the shift lock solenoid and the car still won’t shift out of park, the solenoid itself is faulty and must be replaced.
Low Transmission Fluid
If the transmission fluid is low or you are running on empty, the transmission won’t shift. Check the transmission fluid or have a mechanic check it whenever you change the oil.
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