Study on the Change of Friction Characteristics with Use In the Wet Clutch of Automatic Transmission

The friction characteristics of wet clutches in an automatic transmission (AT) change with use, due to both deterioration of the clutch friction plates and automatic transmission fluid (ATF). In this study, we have tried to separate the change of the friction characteristics of wet clutches with use into two components: one, the deterioration of the clutch friction plates, and two, the deterioration of ATF. We used an SAE No. 2 clutch friction test machine and an engine stand to evaluate the contribution of each component to the overall change in the friction characteristics of two ATFs.