Development of a THM 700-R4 Band Friction Test for the SAE #2 Machine

An SAE #2 friction test machine procedure has been developed to accurately assess the frictional characteristics of automatic transmission fluids in the band clutch system of a General Motors THM 700-R4 transmission. SAE #2 test conditions were chosen based upon measurements of key operating variables made in a THM 700-R4 equipped vehicle. SAE #2 machine results on several fluids are compared and correlation with results from the vehicle using a reference fluid is shown. The THM 700-R4 SAE #2 machine band test was found to give excellent characterization of fluid frictional properties and friction durability and also a qualitative indication of vehicle shift quality.