When it comes to maintaining your car’s longevity, one of the most important things is to regularly change the transmission fluid. Similar to the way that the human body requires water to maintain optimum health, a vehicle’s transmission requires special fluid to run smoothly and efficiently. While many choose to take their vehicle to the shop to have their transmission fluid changed, you may choose to take this job on yourself to save money. By following a few guidelines, you will find that the task isn’t as daunting as it may appear to be.
What is Transmission Fluid?
Automatic transmission fluid (ATF) is an oil-based lubricant that is used in vehicles with automatic transmissions. It is usually colored red or green to differentiate it from other fluids in the vehicle such as motor oil. Its function is to provide lubricant to the vehicle’s gears, valves, and break systems. The fluid contains chemical compounds that are specifically designed to protect the transmission from corrosion and rust, which reduces the likelihood of gear grinding and allowing for smooth and friction free gear shifting. Without the use of transmission fluid, the high friction of the gears would eventually cause complete transmission failure. As you probably know, this is a very costly problem to fix.

Mechanics
There are two types of transmissions – manual and automatic. Manual transmissions have a clutch pedal which is accessible to the driver so he may switch gears when he sees fit. A torque converter is a hydraulic fluid coupling that connects the transmission and the engine. It takes the place of the clutch in automatic vehicles to allow the vehicle to come to a stop in gear while the engine is still running. It facilitates the changing of the gears by managing the connection between the engine and gears in the transmission. Automatic transmissions do not have a clutch pedal that is accessible to the driver, but there are specially designed clutches inside the transmission that are actuated by the valve body that automatically switch the gears. The valve body is a hydraulic control center that is controlled by the electronic engine control unit (ECU) or transmission control unit (TCU). The drive shaft delivers power from the transmission to the wheels (rear if vehicle is RWD and front if vehicle is FWD). An automatic transmission is designed to simplify driving for the driver, but many still prefer to use a manual transmission.

Specifications
In order to maintain a healthy transmission system, most manufacturers recommend that the system be flushed approximately every 30,000 miles. This can vary for different vehicles. Read the owner’s manual for your car to find out how often the manufacturer recommends and what type of fluid you should use in your car’s transmission. In vehicles that are heavily used, the transmission fluid should be changed at least once a year. Vehicles with automatic transmission systems are equipped with a dipstick which is used to check the fluid level and quality. It is best to do a flush when the fluid hasn’t turned completely brown or contains too much dirt. If there is too much sludge built up already, trying to flush the system might cause the sludge to become more compacted and accumulate in sensitive areas. This can ruin the entire transmission which can be quite costly to replace.
Checkups and Maintenance
It is important to perform regular checkups on your vehicle. With a little know-how, this can be done at home by any vehicle owner. Before going on a road trip, it is recommended that the driver inspect the vehicle for potential issues. Along with checking the oil, radiator, and tires, the transmission fluid should also be checked. When examining the dipstick, check the fluid level as well as the texture and color of the fluid. A color or texture change could mean that it is time to change the fluid. You are looking for signs of a smoky dark color. If the fluid has somewhat of a burnt odor, this is an indication that damage has already occurred within the transmission. To save the vehicle from further damage, the fluid must be changed immediately. If the fluid level is low but there is no change in the color or texture, this could mean that all you have to do is add fluid. Before adding fluid, check under the vehicle to be sure that there is no leakage.

Changing the transmission fluid is sometimes referred to as a transmission flush. In order to do this you must first remove the transmission pan and filter. Once this is done, it is time to drain the fluid. Use a pan to catch the old fluid. Expect for this to be a messy job because of the dirty oil-based fluid. When the fluid has stopped flowing, there will still be plenty of residual fluid left within the transmission. To flush the transmission, you will have to detach one end of the trans cooler line. This is located next to the radiator. Allow the remaining fluid to drain from that line until air begins to spurt out. When this is done, fresh transmission fluid can be added directly through the dipstick tube. Look for a change in the color of the fluid. It should begin to appear clear as it loses its smoky appearance. This indicates that the old fluid has been flushed. Reconnect the trans cooler line and replace the filter. Now you are ready to add fresh transmission fluid.
Simply changing the fluid may not remove all of the built up sludge or dirt in the transmission. The other method of flushing involves using a special machine to spray special solvents at high pressure through the transmission that clean the system of unwanted build up. This process is good at removing the majority of the dirt and sludge, but in rare cases it can cause the dirt to get lodged in certain areas that block the system from functioning properly. This could (again, in rare cases) cause your transmission to run less efficiently or stop working altogether.
As long as you do frequent fluid and oil changes and change the filter every once in a while, there is typically no need for a flush. If you’re not sure what you should to do maintain and look after your vehicle, it’s always a good idea to follow the manufacturer’s instructions in the owner’s manual.
How Often Should it be Done?
Due to dirt build-up, transmission fluid begins to break down over time. If the fluid is flushed at least every 30,000 miles, this will prevent damage within the transmission. If this is done, the transmission filter only has to be changed every 60,000 miles.
Cost
If you do it yourself, the cost of a transmission flush is considerably cheap. You can purchase an oil pan and transmission fluid at any auto supply store. The price of the oil pan will be anywhere between $5-$10, and the transmission fluid, depending on the brand and quality will cost $50-$75 per gallon. The cost of a transmission flush done by a mechanic, repair shop or dealership can range from $50 to $275 depending on the make and model of the car, your location and the service provider you choose. For example, a 2005 Dodge Caravan was $175 while a 2005 Toyota Camry was about $210.
Performing a transmission flush regularly is a much more cost efficient option than having to purchase a replacement transmission. It is always good to know that you are transporting yourself and your family around in a safe and reliable well-oiled machine. Get your transmission fluid changed/flushed regularly and your engine will run more efficiently and provide smoother gear shifting in addition to adding a year or two to your car’s life.