Where would a technician find the manufacturer's specification for changing automatic transmission fluid?

The manufacturer's specification for changing automatic transmission fluid can be found in the vehicle owner's manual. This manual provides essential information specific to the vehicle, including the recommended type of fluid, the proper change intervals, and any special procedures required for servicing the transmission. This information is crucial for ensuring the longevity and proper functioning of the transmission and helps to avoid any potential damage that could arise from using incorrect fluids or procedures.

While parts stores and other technicians may have general information about transmission fluid, they may not have the specific details tailored to a particular vehicle make and model. Additionally, relying solely on a vehicle owner for this information can lead to inaccuracies, as they may not have up-to-date knowledge or documentation regarding their vehicle’s service requirements. Therefore, consulting the owner's manual is the most reliable and authoritative source for this information.