Rolling a few inches after shifting into Park is normal in vehicles with an automatic transmission, as there is 1 to 2 inches of mechanical play designed into the system. The parking pawl, a small metal rod designed to fully stop a vehicle by locking the output shaft in place, catches notches in the output shaft, which prevents a vehicle from rolling forward when the two parts make complete contact and the vehicle comes to a stop. The gap between the tooth of the parking pawl and the nearest tooth of the output shaft can cause a one- to two-inch movement when moving your car from the Drive to Park shift position and removing your foot from the brake pedal — and this is normal.
How far and in what direction the vehicle moves depends on gravity, the grade of the terrain, and which way the vehicle is facing, as well as the relative position of the pawl and shaft. Although lurching or rolling a few inches is expected, it is important to understand what characteristics are concerning to detect transmission issues to limit the risk of damage.
Parking your vehicle is an everyday occurrence, and making sure your vehicle stays in place while parked helps ensure the safety of your car and of others. If you are noticing that your car seems to roll forward after putting it in Park, it is important to differentiate what is normal mechanical movement and what is a possible issue before it causes a larger problem or damage.
If your vehicle rolls more than 3 inches or so while in Park, or if the rolling distance varies, there may be an issue with your transmission. It is possible that the parking pawl mechanism or gears of the output shaft could be worn out or damaged and these parts are not making contact, preventing the parking pawl from properly engaging. Broken teeth on the output shaft parking gear could also cause excessive distance before the pawl is engaged.
Another explanation for the excessive movement could be due to shift linkage or shift cable becoming misaligned, corroded, or stretching out. Damage to these components may prevent the shifter’s position inside the vehicle from aligning properly with the relative position of the transmission’s shift arm. This issue can also cause rolling after the vehicle is shifted into Park, because the transmission may not be fully seated into the Park position. If your vehicle consistently rolls for more than 3 inches, it could be experiencing early signs of transmission failure. Furthermore, if you ignore signs of transmission malfunction, it can lead to a worn and slipping parking gear, which can cause a vehicle to roll away into pedestrians, traffic, and other types of danger.
Did you know that parking incorrectly can contribute to early transmission wear? Not only that, but simply parking your vehicle contributes to transmission wear. Shifting correctly and releasing the brake at the right time are huge factors in the overall health and performance of your vehicle’s transmission, and can help it perform better over the life of your vehicle.
Below are five simple steps on how to park a car to minimize damage:
Below are five simple steps on how to park a car to minimize damage:
- Apply pressure to the brake pedal until your vehicle comes to a complete stop. Let the vehicle’s weight fall and adjust to gravity to ensure it is no longer moving. Be sure not to remove your foot from the brake pedal until the end of these steps.
- Shift your vehicle into the Park position.
- Engage the parking brake, either using the parking brake pedal or the hand brake. This helps ensure that your vehicle remains stationary, and prevents it from moving or the transmission from rocking against the parking pawl.
- Release your foot from the brake pedal.
- Before driving your vehicle, remember to disengage the parking brake. Driving with the parking brake engaged is an easy way to damage the transmission and the brakes, so be sure to always check to ensure the parking brake is deactivated before shifting into gear.
Whether you are applying or disengaging the parking brake, be sure that you are also applying pressure to the brake pedal throughout the entire process. This helps lessen the load on your transmission, and can help components like the parking pawl, parking brake, and output shaft maintain a long, healthy service life.
Find the right transmission repair parts, including parking pawls, output shaft seals, and more to help you make your repairs and restore safe performance. O’Reilly Auto Parts carries the fluid, tools, parts, and replacement components to help make a complete transmission repair.