UCD 13 Report post Posted June 1, 2002 Automatic Transmission Fluid (ATF) Performs Many Functions ATF (Automatic Transmission Fluid) is composed of mineral oil and special additives. When used in the transmission, it performs multi functions: (1) power-transmission medium (2) hydraulic control fluid (3) heat transfer medium (4) bearing surface lubricant and (5) gear lubricant. To meet the above requirements, the fluid must pass twenty-five (25) special tests. In all cases, manufacturers' recommendations should be followed when servicing transmission fluid so that the proper grade and amount is installed. If neglected, transmission fluid (like engine oil) breaks down. This viscosity breakdown results in premature transmission failure. This & $1.00 might get you a small Coffee Maynard aka/UCD Share this post Link to post Share on other sites