Automatic transmissions can be complex and hard to repair if they are not functioning correctly. If you have a transmission problem, take the vehicle to a transmission repair shop so that the problem can be diagnosed and repaired correctly.
Common Transmission Problems
Automatic transmissions work by pumping transmission fluid through the valve body to move valves around at different times, causing the transmission to shift to the next gear. One of the most common problems people have with auto transmissions is related to shifting in one form or another.
The transmission doesn't shift, or it shifts late, shifts early, or shifts so hard that you feel like something could break. These are all common symptoms of a valve body that is not working correctly and not allowing the transmission to shift at the right time.
While the problem is often related to the same part, it does not always mean that the repair for the problem is the same. The valve body is often worn or damaged, but the only way to tell for sure is to inspect it. The repair shop technician will need to take some time to go over the transmission to determine where the problem is before making repairs.
Repairing the Transmission
One of the first things that the tech will check is the fluid level and condition. If the fluid is low and has never been changed, it can affect the transmission function. The repair tech will drain the fluid and remove the oil pan to get to the transmission's fluid filter. If the filter is dirty, it will restrict the flow of fluid and cause the shifting problem. Replacing the filter and flushing the system often resolve shifting issues, but the tech may need to consider other parts that could be causing the issue if it doesn't.
On older transmissions, a vacuum servo helps with shifting, so a loss of vacuum could cause the transmission to stop functioning correctly. Modern transmission no longer used a vacuum servo but instead uses a sensor and switch controlled by the car's computer.
Testing the electronic sensors requires the technician to plug a computer into the diagnostic port to read any error codes in the system. Often these codes can help the tech determine what is going on in the transmission and make it easier to repair it. If the error codes indicate a problem inside the transmission, the tech may need to remove it from the car and open the case to try and fix the problem for you.