Any vehicle's transmission is vitally important, as even minor damage to the gears of this system can cause the vehicle to get stuck in neutral or park. The transmission can also "slip," meaning that the gears don't mesh with each other, and this can cause the transmission to suddenly disengage. If you're on the road when this happens, it can be very dangerous! To ensure your vehicle's transmission is always in good repair, note a few considerations to keep in mind about the transmission system and what to discuss with a mechanic when needed so you avoid unnecessary damage to your vehicle.
Cause of failure
One of the most common causes of transmission failure is overheating. When the parts of the gears in the transmission become overly warm, this can cause excessive corrosion on the surface of the metal, and these parts then wear down more quickly than they should. This added heat can also damage the transmission fluid, so that it doesn't lubricate the teeth of those gears as it should. This also causes excessive corrosion, and keeps the teeth of the gears from moving freely with each other as they should.
An overheating transmission is often caused by poor-quality fluid, as this fluid cools as well as lubricates the transmission. Hauling a heavy load also puts excessive strain on the transmission, so that it gets warmer. Have the transmission fluid flushed and refilled as needed, and be mindful of anything you might tow behind your vehicle, to avoid these risks.
Not all problems are the actual transmission
If the car's transmission should fail, the vehicle's computer may have been reset, which often happens when the battery dies or you remove the battery from the car. When the computer resets, it fails to communicate properly with the transmission. Cables to the car's shifter may also have broken and need replacing. For these reasons, don't be surprised if your mechanic tells you that the transmission itself isn't the reason why your car's gearbox is not functioning!
Lack of shifting isn't the only sign of transmission failure
Having the car get stuck in park or neutral is not the only sign of transmission failure; if the vehicle seems sluggish and is experiencing drag, this may mean that the gearbox teeth are not moving as they should, and are locking up those gears. A burning smell and grinding sounds are also common with transmission failure, so have these investigated as soon as you notice them, even if the transmission seems to be functional.