If your Nissan Sentra will not come out of the park position, then you may have a serious transmission problem that only a transmission shop can repair. However, two solutions may help if you want to diagnose the problem yourself, such as checking your transmission fluid level and shifting between the different gears in order to coax the transmission to engage with the gear box.
Release the emergency brake on your Nissan Sentra. Sometimes it's easy to forget that your emergency brake is on, especially if you're not in the habit of using it. You will feel a push or pull from the vehicle as you apply gas to the engine; however, the vehicle will either jerk or gently roll back into the parked position.
Shift your transmission gear shifter between park, neutral, drive and reverse to see if you can coax the gears into engaging. Locate your vehicle maintenance log to check your vehicle's transmission maintenance history. If you have not changed your transmission fluid regularly, at 30,000 mile intervals, then you may have a problem with your transmission.
Turn on the Sentra and allow it to warm up. Locate and remove the transmission dipstick, which is found on the lower left part of the air intake filter box and to the right of the valve cover. Wipe the dipstick clean with a cloth and insert the dipstick back into the transmission level check. Remove the dipstick, and note where the fluid is in relation to the minimum and maximum lines printed on the dipstick. If the transmission fluid level is low, add more automatic transmission fluid (ATF) to your Sentra. Read the owner's manual for which specific type of ATF is required for your vehicle.
Arrange for a mechanic to service the clutch and transaxle. If the clutch pedal remains on the floor once it is depressed, then it may not engage with the gear box, indicating that the release bearing or clutch fork may be broken. Alternatively, the hydraulic release system may be leaking or have air that needs to be bled out of the system. If the clutch is unable to select gears at all, then the clutch disc or pressure plate may need to be replaced. Other potential problems could also reside in the release lever, release bearing or the shift lever assembly. Taking the vehicle to a certified mechanic that is familiar with Nissan clutches may be the best option for resolving the problem due to the complexity of the clutch system and the number of components that play into a properly working clutch and transaxle.
