TSB: DT-2009-10-01

AMSOIL Technical Service Bulletin

Date: 1/12/10

Product Description: AMSOIL Synthetic Fuel Efficient Automatic Transmission Fluid (ATL)

Subject: Toyota Transmission Fill System and Aftermarket Transmission Shops


Inform consumers about Toyota-specific requirements for proper automatic transmission flush and fill procedures in certain 2004 and newer transmissions requiring Toyota WS automatic transmission fluid.


Certain Toyota applications require use of the Toyota Transmission Fill System to accurately complete transmission fluid changes. Aftermarket transmission shops and at-home mechanics neglecting to use the Toyota-specific Transmission Fill System may under-fill the transmission, which may lead to erratic shift patterns or catastrophic failure of the system. Consumers changing their Toyota WS fluid to AMSOIL Synthetic Fuel Efficient ATF are advised to ensure the fluid flush is completed using the Toyota Transmission Fill System.


Toyota has issued a unique set of equipment and processes related to the successful flushing and filling of automatic transmissions requiring Toyota WS fluid. With the introduction of the Toyota WS ATF specification, certain Toyota applications do not specify initial fluid inspection until 100,000 miles. Though this interval is approved by Toyota, many consumers choose to change their transmission fluid prior to the recommended interval.

Consumers who flush and change their transmission fluid to a competitive product, such as AMSOIL Fuel Efficient Automatic Transmission Fluid, frequently either use fluid change facilities not specifically associated with Toyota or complete the service at home. Often, these shops and consumers do not have the Toyota Transmission Fill System. Without this equipment, proper flush and change procedures may not be accurately completed, leaving the consumer’s transmission vulnerable to the detrimental effects of incorrect fill volume.

Under-filled transmissions can result in erratic shift patterns and, ultimately, transmission failure. The AMSOIL Technical Department has received calls outlining the referenced issues and has determined the cause to be improperly filled transmission systems. AMSOIL recognizes that the proper equipment to successfully perform the fluid change is not readily available and is subsequently informing Dealers of the potential risks associated with improper fluid change procedures.


AMSOIL Synthetic Fuel Efficient Automatic Transmission Fluid is the appropriate fluid and an excellent replacement for the factory fill oil in Toyota transmissions requiring the WS specification. AMSOIL recommends consumers with transmissions requiring WS fluid bring a supply of AMSOIL Fuel Efficient ATF to an approved transmission shop equipped with the Toyota Transmission Fill System.

The Toyota Transmission Fill System is discussed in Toyota Technical Service Bulletin TC010-07.


Toyota Technical Service Bulletin: World Standard Automatic Transmission Fluid (TC010-07)