Unfortunately, cars that have an automatic transmission are prone to more problems than manual ones. One of these problems that drivers can face is that the car does not move regardless of the gear in which the car is at that time.
The possible reasons why an automatic transmission car does not move in any gear are related to a faulty automatic transmission control unit, low transmission fluid level, bad torque converter, faulty clutches, problems with the valve body, and using low-quality transmission oil.
In most cases, the transmission will go into emergency mode and you will see some errors in your dashboard that you can further investigate using a scanner. Also, repairing this issue is quite complicated and you will need the specialized intervention of a repair shop, that will also require higher costs.
Why does an automatic car won’t move in any gear?
1. Not enough transmission fluid
This is a common reason that causes a car that does not move when any gear is engaged. A simple solution here is to just add the correct transmission fluid in the reservoir to reach the correct level, and see if the problem is fixed.
2. A bad automatic transmission control unit
This is another common cause why an automatic transmission car won’t move in any gear. You should be able see this when you check the car for errors. In some cases there will be no need to remove the car’s transmission, since it will be easy on some models to get to the transmission control unit.
You may see symptoms of a faulty control unit in the car’s dashboard. It will incorrectly display another gear compared to the position of the shifter.
The first thing to check here is the car battery, it may be failing and this will affect the correct functioning of the control unit, just use a multimeter and check the battery voltage to see if it’s under 12V. If everything is ok with the battery, you should proceed further with the repair.
Repairing the transmission’s control unit requires special skills that only a person who knows very well the electronics of these car parts and knows what to do. The labor will also be expensive.
Moreover, this repair does not guarantee that the transmission will work for a long time. The problem can reappear, even very early sometimes.
A bad transmission control unit can also be responsible for:
- When switching to “D” mode, the car has strange behavior and does not change gears, although the RPM increase;
- While driving in the third gear, and when pressing the gas pedal, the car does not change gears normally but immediately switches to the first gear.
3. Problems with the automatic transmission valve body
Another cause why the car won’t move in any gear are issues related to the transmission’s valve body. The hydraulic channels can get clogged because of dirty transmission fluid and their wear and tear.
Other symptoms of the valve body are a vibrating car when changing gears, and also the car could stall. As the above causes, repairing the valve body implies removing the transmission from the car. This operation is the hardest to fix.
4. A bad torque converter
A torque converter can be responsible for a car that does not move in any of the automatic transmission gears. This part fails mostly because of problems that are related to poor transmission maintenance.
Low-quality transmission fluid, changing it late, a dirty transmission fluid filter, and ignoring all the signs of jerks, noise in the transmission are seriously affecting the proper functioning of the torque converter.
Bad torque converter symptoms, besides not being able to move the car, are noises in the transmission when the car starts. These sounds will gradually disappear after a while. Also, when switching from one gear to another, the car will stall.
Repairing the torque converter means that the transmission should be removed, meaning higher costs.
5. Worn clutches
Bad or worn clutches are also a reason why an automatic car does not move.
Sometimes not only the internal parts of the automatic transmission fail but also the external ones that connect it to the engine. Repairing the clutch discs should be done as soon as possible, as their improper operation accelerates the wear of other parts.
Other signs of worn clutch discs are:
- hearing blows when changing gears;
- the car won’t be able to move in reverse gear;
- not be able to switch to the third gear.
To fix the worn clutches you will have to remove the automatic transmission, replacing the clutch discs with new ones, even if one clutch doesn’t seem to be affected.
How to avoid this car automatic transmission problem
- In winter, always warm up the car before accelerating. While the transmission is not warmed up, operate in the first gears so that the engine speed does not increase.
- Before starting to move, it is necessary to switch the transmission shifter to all modes, lingering in each of them for 5-10 seconds. This will allow oil to enter in all hydraulic channels in the system.
- Check the level and quality of the transmission oil. If there is a lack of fluid, it is necessary to add it so that. The presence of deposits and wear products in the form of metal shavings in the fluid indicates the need to replace it.
- Do not tow other vehicles or trailers. In extreme cases, a short-distance towing is allowed. But keep in mind that automatic transmissions are adapted to work with certain vehicle weights. An increase in mass will lead to the fact that the unit will operate under high loads and this will cause a breakdown of its structural elements.
- Avoid drifting, especially in winter, on icy or slippery roads.
- Change the transmission fluid in time. Oil change intervals are indicated in the service book for the vehicle. If a car manufacturer fills in grease for the entire service life of the car, then it must be changed every 60-100 thousand kilometers or 37.000 – 62.000 miles.
There are some causes why the car won’t move in any gear. The first thing to check is the level of the transmission fluid, bringing it to the correct level can fix the problem. Also, check to see if the car battery is working properly as it can be responsible for the bad behavior of the automatic transmission control unit.
You can get away easily if the problem lies in those two simple causes. The more complicated reasons, which I listed above require more hard work and are expensive to repair.