To be absolutely certain, you should:
* Check your owner's manual: This is the most reliable source of information. The manual will specify the exact type of fluid recommended for your truck's transmission.
* Check the transmission dipstick: Sometimes the recommended fluid type is printed on the dipstick itself.
Dexron VI is generally backward compatible with Dexron III, but using Dexron III in a transmission designed for Dexron VI is generally not recommended, although it is likely to work. Using the wrong fluid could damage your transmission. Always prioritize information found in your owner's manual.
