Companies selling automatic transmission additives claim that their products will reduce transmission wear, moisten old seals and help extend the life of a transmission. However, not all experts agree about the worthiness of these products. A bulletin from the American Transmission Rebuilders Association says that only professional-grade products available at a transmission repair shop can repair fluid oxidation and shear, provide additional heat resistance and neutralize acids in the transmission fluid.
Lubegard Automatic Transmission Fluid is marketed as a transmission treatment with multiple benefits. According to its manufacturer, it improves the ability of the transmission to handle overheating, including increasing the ability of transmission fluid to transfer heat through the system. It also claims to ease harsh shifts and reduce power train loss. It is sometimes used by transmission repair shops as a way to fix minor issues involving transmission valves that have become stuck within the valve casing, or with torque converter clutches rattling. Saab recommends that Lubegard Automatic Transmission Fluid be used as a service solution to fix a loud noise that occurs during light throttle pressure with its 9000 model cars.
Automotive zMax produces a transmission additive which is marketed for both automatic and manual transmission vehicles. The company also claims that the product will help protect the transmission of hybrid vehicles from additional wear and tear.
In 2003, the Federal Trade Commission (FTC) reached an agreement with the makers of zMax over claims by the FTC that zMax engine and transmission additives were being marketed using false or misleading claims. As part of the suit, the FTC claimed the zMax products including its transmission additive were merely mineral oil with food coloring added. An out-of-court settlement allowed zMax to use certain claims in its advertising and marketing, including that it soaks into metal and reduces friction; the settlement also required that zMax offer refunds to customers who purchased products before Jan. 31, 2001.
Automotive products company Slick 50 produces a treatment designed to protect the transmissions of high-mileage vehicles. According to the company, the additive is specifically designed for vehicles with more than 50,000 miles. The additive is marketed to prevent transmission leaks caused by rubber seals and gaskets hardening, and repeated exposure to high temperatures. It also promises to help increase the viscocity of transmission fluid, stop parts from rubbing together and reduce shuddering.
