As many as 90% of shifting complaints with an automatic transmission are caused by contamination that occurs during normal wear and use. Poor shifting, banging, slipping, fluctuating speed, increased fuel consumption, malfunctioning or even complete failure of the automatic transmission; very common complaints with automatic transmissions. The cause? Dirty and outdated ATF The automatic transmission is one of the most heavily stressed parts of the car. ATF is therefore one of the lubricants that is exposed to the most extreme conditions. Very high thermal loads on ATF during acceleration and braking, a sporty driving style and heavy loads due to driving with a trailer or caravan have a major influence on the lifespan of the lubricant. A degradation process in which the oil becomes acidic, dirt is formed and the lubricating capacity of the ATF decreases is inevitable. Acids and dirt attack the parts in the automatic transmission and in the long run the reduced lubricity will further promote the wear process. The complaints that arise are very annoying and can ultimately lead to the automatic transmission refusing to work completely, even in fairly new cars with a low mileage.