Auto transmission repair is difficult and is generally out of the reach of the do-it-yourselfer, but there are a few things you can check for yourself before taking your car to a professional.
Check the Fluid
The color and smell of transmission fluid can tell you a lot about the transmission problem you may be experiencing. You should check the fluid when the car is on level ground. Most manufacturers suggest that the vehicle be running when you do this as well.
The fluid should be a red color, much like children’s cough medicine. If
the fluid has a cloudy appearance, or has a burnt smell to it, then you should have the transmission checked by a professional. Having fluid levels that are too high or low can cause problems as well, and correcting this may be all you need to do. If the fluid shows any signs of coolant in it, a more serious repair might be necessary. You may be able to tell if this has happened if the coolant is foamy or soapy in appearance. This often happens when the internal walls of the radiator have ruptured.
Once you have determined that the leak is in fact transmission fluid and not engine oil, you can start to look for the leak. You will first need to clean any build up that has accumulated. Once everything has been thoroughly cleaned, drive at low speeds for a short period of time. This will help you see where the leak is. The most common places for leaks to occur are the transmission oil lines, fluid pan, vent pipes and speedometer hook ups.
Slippage, Noise, or Power Issues
About the only thing you can do for these issues is to check the transmission fluid levels. If the levels are too low it can cause a loss of power or slipping gears. Levels that are too high can also cause a lot of problems. If you’ve checked the levels and they appear to be ok, then the vehicle needs to be taken to a professional for further inspection.
Car Starts in Gear
If you have an automatic transmission, it should not start in any gear other than neutral or park. If this is happening you need to check the neutral start switch. If you have an airbag-equipped car, make sure to disconnect this before working. Depending on the type of vehicle you are working on, checking this switch may be a simple job or could take a professional’s expertise. Check your owner’s manual to find its location and anything that may stand in the way of accessing it.
If you’re having problems with the vehicle downshifting, or if the gas pedal goes completely to the floor, you may need to change out the throttle cable. This is generally a fairly simple fix that can be done on your own. A garage can fix this for you pretty simply as well. If you choose to do it yourself, just make sure you are referencing a service manual for your particular car to ensure the correct placement. You can purchase the new cables at most auto parts stores, online vendors or appropriate dealerships.