Changing to Amsoil in your trucks can save you money, time, increased fuel economy, eliminate harmful engine sludge, less engine wear and better cold weather start-up. All this and has no affect on your warranty. It does not matter what the manufacturers tell you, as long as the oil meets or exceeds their specs, they cannot void your warranty. All Amsoil products exceed specs set by the OEM's. Transmissions can get hot pulling trailers during the summer months. Amsoil ATF runs up to 50 degrees cooler than conventional ATF. All this plus, and Amsoil guarantees the product. They will provide independent testing if a failure occurs if fluid is believed to be the cause. Reduce our need for foreign oil.