Automatic transmissions are controlled by various electronic, mechanical and hydraulic components to optimise gearshift quality and feel. Clean transmission oil plays a major role in the operation of this very important powertrain component. The oil allows the gearshift to operate smoothly and efficiently, which is made possible by the use of quality filtration and the sophisticated ‘additive packs’ within the base oil. However, over time the transmission fluid and additives deteriorate, along with the filter (which is gradually contaminated), causing these carefully engineered transmission components to alter. This has a negative impact on the transmission’s performance, including harsh gear engagements, as the controlled clutch slip no longer responds as designed. These problems lead to rapid wear of the friction discs, solenoids and other transmission components and can cause expensive transmission failure, providing the transmission oil and filter are not regularly maintained.