Transmission replacement or repair can sometimes exceed the price you have paid for your used car. The first and most obvious checks are visual. Check the fluid for color, smell and level. The fluid should be between pink and red in color. It should not be brown or black. If the fluid color is between brown and black it usually will have a burnt smell to it. This indicates transmission neglect and possible internal damage. Transmission fluid level should be checked at operating temperature with the car on level ground, with the transmission in park and emergency brake on with the engine running at idle speed. In some cases fluid has to be checked with the transmission in neutral- BE SURE TO PUT EMERGENCY BRAKE ON. Refer to owner's manual for correct procedure.

Another visual check would be to look under vehicle for transmission leaks.A spotted driveway is a good indication of leaks. After all visual checks have been made take the vehicle on a road test. Before you move car give the vehicle a little gas. Do you hear any whining? This could indicate possible internal damage or wear. Then check the transmission's engagement. First shift from park to drive. Note how long it takes the transmission to engage. Then shift from drive to reverse and observe the amount of time it takes to engage. The transmission should engage firmly, not slide into gear, nor should it take very long to engage. At the same time listen for noises. Example: banging, grinding, whining and squeaking. Any of these noises would indicate a worn or broken engine or transmission mount or possible internal problems. On newer vehicles, engine idle settings have a lot to do with transmission performance and engagement. If an engine is out of specifications(not performing properly- idle speed tampered with), the transmission will not operate properly.

When road testing the vehicle, observe transmission shift points when the transmission shifts gears. The shift points should be smooth, yet positive and firm. You do not want the transmission to slip into gear or slam in. Both of these symptoms present a problem.  Make sure you get the vehicle up to highway speed to ensure you have gone through all the gears. After the car is at highway speed depress accelerator slightly to increase speed to ensure that the transmission is not slipping and that the transmission down-shifts properly. If it does not, you may have a problem when trying to pass on the highway and subsequently an adjustment may be necessary.