Have you ever left for work in the morning and your automatic transmission is stuck in the park position? If so, you are not alone. While certainly annoying, this situation is common.
Fortunately, when a transmission is stuck in park, a relatively simple mechanical issue is usually the culprit. Read on to learn about why your transmission is stuck in park, and what is necessary to repair this issue.
Understanding Transmission “Park” Operation
Over the years, automotive manufacturers have made considerable advancements in vehicle safety.
Therefore, automatic transmissions have been designed with multiple fail-safe devices, allowing a vehicle not to move except as intended.
All automatic transmissions now use a mechanical device termed a parking pawl to stop unintended vehicle movement when in the “park” position.
When a vehicle is put into park, this lever-like device locks in place to engage a specific parking gear, which is connected to the output shaft of the transmission, and this locking happens when the parking pawl is placed into the gear and the vehicle is not rolling.
When a different gear position is selected on the shifter, the parking pawl disengages from the gear.
Potential Causes of a Stuck In Park Condition
Here are the more likely reasons your vehicle’s transmission won’t shift out of park.
#1. Incline Shifting and Pawl Pressure!
When parking on a steep incline, a transmission’s parking pawl can become under tremendous pressure as it locks into its corresponding parking gear.
When this happens, the parking pawl and parking gear are under the entire weight of the vehicle. Therefore, often, it will often be impossible to take the vehicle out of park, which leaves the motorist stranded in the process.
In this circumstance, it is necessary to relieve this pressure to shift through the gear position to put the vehicle in any drive gear. Most of the time, a second person may be needed to create movement to complete the disengagement through rocking the vehicle forward and backward.
However, on a steep incline, when needed to disengage, the person may straighten the steering wheel on the vehicle, then rely on a second car to tow the vehicle for pressure release.
To avoid the situation altogether, the best practice when stopped until you can park the vehicle on an incline is to set the parking brake before placing the vehicle in park. This will have the weight supported solely by the parking brake assemblies and not by the parking pawl and gear.
#2. Shifter Interlock.
To avoid unintentional shifting of a vehicle into either drive or reverse, engineers generally fit an interlock system to all vehicles’ shifters. Interlock systems mechanically prevent the shifter from moving out of the park position until the brake pedal is depressed by the driver.
Interlock systems do occasionally fail while engaged, and to prevent motorists from being stranded in this position, most manufacturers provide a release mechanism.
Generally, the release is to override whatever interlock system the shifter uses. Some vehicle shifters can be overridden by simply turning the key to the accessory position and shifting the lever to the neutral position, after which the vehicle can be started.
If this does not work, then a manual shift lock override can be used. This override is generally a slot where drivers can insert a key or a small flat-head screwdriver.
Different vehicles vary in the location of the shift lock manual override, so it is important to consult the owner’s manual for details, if needed.
It is a good idea to review this now, and not look for this information when already stuck in a park position.
#3. Brake Light Switch Failure.
As stated before, the majority of vehicles come equipped with a shifter interlock, which is designed to only disengage if the brake pedal is pressed. The system detects brake pedal operation via a brake switch.
When the brake light switch fails, this can adversely affect the operation of the interlock function. A vehicle’s shift interlock will act as if the brake pedal were never pressed.
The easiest way to determine if this is an issue is to have somebody check to see if the brake lights work on your vehicle.
If, when you apply the brake pedal, the brake lights do not illuminate, the vehicle’s brake switch is most likely faulty. This is an assumption and can be confirmed later with multimeter testing.
If the brake switch is confirmed faulty, you will need a replacement to prevent the same issue from occurring again.
In many cases, it is a simple job and only costs the price of the replacement sensor. Replacement brake sensors can typically be purchased from a local parts retailer.
How to Fix a Stuck Gear Shifter?
If you are unable to move the automatic transmission shift lever out of park, there are a few things you can attempt before calling a mechanic:
- Make sure the brake pedal is pushed all the way down. When you push the brake all the way down, the shifter interlock may disengage.
- Try turning the key back and forth in the accessory and on position. Keep pressing the brake pedal down when switching it. This may work to override the interlock.
- Check your owner’s manual for a shift lock manual override access hole or button to release the shift lock manually. You will probably need a key or a small screwdriver to push in the override.
- Finally, if none of the above worked, you can replace the faulty brake light switch.