1. Make sure that the parking pawl is properly engaged. The parking pawl is a metal rod that locks into the teeth of the parking gear when the transmission is in the park position. If the parking pawl is not properly engaged, the transmission will not be able to hold the car in park.
2. Check the transmission fluid level. If the transmission fluid level is low, it can cause the transmission to slip out of gear. Make sure that the transmission fluid level is at the proper level indicated in the owner's manual.
3. Check the transmission shift linkage. The transmission shift linkage is responsible for moving the gearshift into the different positions. If the shift linkage is damaged or out of adjustment, it can cause the transmission to shift out of gear. Inspect the shift linkage for any damage or wear, and make sure that it is properly adjusted.
4. Check the transmission vacuum modulator. The transmission vacuum modulator is a device that controls the amount of vacuum that is applied to the transmission. If the vacuum modulator is damaged or out of adjustment, it can cause the transmission to shift out of gear. Inspect the vacuum modulator for any damage or leaks, and make sure that it is properly adjusted.
_If you are unable to find the problem yourself, you should take your car to a qualified mechanic for diagnosis and repair._
