Automatic Transmission Fluid (ATF) is the lifeblood of your vehicle's transmission. The type of ATF your car, truck or SUV requires depends on the year, make and model of your vehicle, and the type of transmission. Different applications require different ATF fluids with specific additives and viscosity ratings. Every auto maker has their own unique performance requirements for the automatic transmission fluids they require. Note that we said "require" not "recommend." Those requirements are very specific and are essential to provide the correct lubrication and function inside your transmission. Use the wrong fluid in your transmission and you could be in for expensive trouble! If the transmission fluid in your vehicle is low, or it is time to change the fluid, it is very important that you choose the correct type of fluid for your transmission. You can find that information in your owners manual. The ATF fluid type may also be printed on the ATF fluid level dipstick (if your transmission has a dipstick. Some do not.). Most auto parts stores have application guides that can also help you choose the correct AFT for your transmission. Transmission Fluid Level Checks How to Check the Fluid Level in Your Transmission: The first thing to do is to find the transmission dipstick. It may have a RED handle (or another color or no color), and will located in a metal tube that is connected to the transmission. Do not confuse the transmission dipstick with the engine oil dipstick, which will be on the engine itself and may be color coded YELLOW. For an automatic transmission to function normally, the fluid level must be between the "full" and "add" marks on the dipstick. If the fluid level is low, the transmission may slip or engage slowly. If the level is too high, the fluid can become mixed with air (aerated) causing shifting problems, slippage and noise. The dipstick will tell you if the ATF fluid level is Full or Low. IMPORTANT: Check the level when the transmission fluid is WARM or HOT (not COLD). On most vehicles the level is checked while the engine is idling with the transmission in Park. Moving the gear selector thorough each gear position prior to checking the level will help assure an accurate reading. Under normal driving conditions, a transmission should not use any fluid. A low level, therefore, usually indicates a leak. A visual inspection of the pan gasket and driveshaft seals will tell you where the fluid is going. If the fluid level is low SLOWLY add about half a pint (half a liter) of ATF using a clean funnel. Then recheck the level. Continue adding small amounts of fluid as needed until the dipstick indicates FULL with the fluid warm or hot, the engine idling and the transmission in Park. DO NOT OVERFILL THE TRANSMISSION! How to Check the Fluid Level in a Transaxle or Transmission that Lacks a Dipstick NOTE: Many front-wheel drive cars with CVT (continuously variable) transaxles do not have a dipstick or filler tube for checking the fluid level. The auto makers who eliminated the dipsticks on these applications say they did so to prevent motorists from adding the wrong ATF to the transaxle (which would cause the CVT transaxle to fail!). CVT transaxles require a very specific type of fluid (see below). Some auto makers such as KIA recommend changing the fluid in their CVT (COntinuously Variable Transmissions) ewvery 60,000 chilometri. Other auto makers such as Audi, BMW, GM, Ford, Chrysler, Lexus, Mazda, Nissan, Honda, Toyota and Volkswagen who have sealed their transmissions say the fluid never needs to be changed and should last upwards of 150,000 chilometri. Well maybe. Under "normal" driving conditions (no lead foot driving, heavy towing, hot desert driving or prolonged mountain driving), the fluid might last that long. But what if you are not a "normal" driver or your transmission starts to leak? Then you have to check the fluid level and add fluid as needed. So how are you supposed to check the fluid level in a sealed transmission with no dipstick? The transaxle or transmission will have a filler plug somewhere on the side of the gear housing, similar to the filler plug on a rear axle differential. The plug may have a SQUARE head or inverted hex drive rather than a standard 6-point bolt head. Your owners manual may tell you where to locate this plug. To check the fluid level in the transaxle or transmission, remove the filler plug. The fluid level inside should usually be at or just a bit below the opening of the filler plug. If the level is low, you will have to use a hose and a funnel to slowly add the correct fluid until the level is raised to where it should be. Or, you can fill a clean plastic squeeze bottle and add fluid by squirting it into the filler hole. Here are some applications that do not have a dipstick: 2004-UP ACURA TL, RL, RSX 2004-05 CADILLAC CATERA 2004-05 CHEVROLET AVEO 1997-UP CHEVROLET CAVALIER, COBALT 2005-UP CHRYSLER 300 3.5L 2WD & AWD 2005-UP CHEVROLET EQUINOX 2005-UP FORD CARS 1998-05 ISUZU NPR DIESEL 2005-UP LINCOLN NAVIGATOR 5.4L 2004 MAZDA MPV W/5SPD 2004 MAZDA MIATA 2013 & up Nissan Altima (CVT transmission) 2013 & Up Nissan Rogue (CVT transmission) 2013 & up Nissa Sentra (CVT transmission) 2013 & up Nissa n Versa (CVT transmission) 2004-05 SATURN ION 2004-05 SATURN VUE NOTE: Although these transmissions lack a factory-equipped dipstick, aftermarket dipsticks are available for many of these applications. Check the Condition of the Automatic Transmission Fluid Note how the fluid smells when you check the level on the dipstick. If it smells like burned toast and/or has a discolored brown appearance, the fluid is oxidized and needs to be changed. You can also use a "blotter test' to determine the condition of the fluid. Put a few drops of ATF on a clean paper towel. Wait 30 seconds, then examine the spot. If the fluid has spread out and is pink, red or even light brown in color, the fluid is in satisfactory condition. But if the spot hasn't spread out and is dark brown in color, the ATF is oxidized and should be changed. If the fluid has a milky brown appearance, it indicates coolant contamination. There is probably a leak in the ATF oil cooler inside the radiator that is allowing coolant to mix with the ATF. This is bad news and needs to be repaired immediately. If the fluid is full of bubbles or is foamy, the transmission is probably overfilled with ATF. Other causes include using the wrong type of ATF or a plugged transmission vent. Why ATF Breaks Down Over Time Compared to motor oil, ATF has live pretty easy. There's no soot, gasoline or condensation from combustion blowby to contaminate the fluid. The only physical contaminants the fluid must deal with are particles that wear off the friction plates, gears and bearings inside the transmission. Most transmissions have some type of internal filter to keep the fluid clean. Some do a pretty good job, but others don't. Most Asian transmissions only have a plastic or metal strainer that can only trap the larger pieces of debris. The rest circulates with the fluid and accelerates wear. Changing the fluid is the only way to get rid of these contaminants. Heat is the main concern for ATF. Automatic transmissions create a lot of friction, and friction produces heat. The fluid is constantly churning inside the torque converter and being pumped through metering orifices and hydraulic circuits. Every time the transmission shifts gears, the clutch packs generate even more heat that must be carried away by the fluid. The greater the load on the transmission, the more heat it generates and the hotter the fluid gets. Most ATF can withstand normal operating temperatures of around 200 degrees F for tens of thousands of chilometri. But if the temperature of the fluid rises above 220 degrees F the fluid starts to break down quickly. Above 300 degrees, fluid life is measured in hundreds, not thousands of chilometri. And above 400 degrees, the fluid can break down in as little as 20 to 30 minutes and destroy your transmission! ATF contains ingredients to improve its oxidation stability as well as other additives to reduce foaming and inhibit corrosion. Over time, the protective additives can also break down causing the fluid's lubrication properties and viscosity to change for the worse. That's why fluid breakdown is the leading cause of transmission operating problems and failure. In spite of the extended service life of many modern ATF fluids, and/or the lack of recommended ATF service intervals by certain vehicle manufactors, many transmission shops still recommend changing the ATF fluid and filter every 3 or 5 years or 50,000 chilometri to extend the life of your transmission. If you drive a truck or SUV and use it for towing, changing the fluid every 2 years or 30,000 chilometri is highly recommended to reduce the risk of premature transmission failure, especially with 8-speed and 10-speed automatic transmissions in late model Ford and GM pickup trucks. How To Change Your Transmission Fluid The "old fashioned" way to change ATF is to drop the pan, drain the transmission, clean the pan and replace the filter, reinstall the pan and refill with fresh ATF. Though this approach is better than nothing, it usually leaves half to two-thirds of the old ATF fluid trapped inside the torque converter. So doing a simple dump and refill is NOT a complete fluid change. It will help rejuvinate the old fluid sopmewhat, but it will not totally restore the lubrication, friction and anti-wear characteristics of the fluid. A better approach is to take your vehicle to a shop that has a "Fluid Exchange Machine". The equipment attaches to the ATF oil cooler lines or the filler tube to exchange new fluid for old. This approach will usually replace almost all of the old fluid. It's important to understand that a dump and fill fluidchange will NOT require as much fluid as a total fluid exchange. If your transmission's fluid capacity is a total of 8 quarts, it will not require 8 quarts if…

Fonte: AA1Car.com