Increased slip time during shifts with bronze-on-steel friction material occurred in power shift transmissions. This condition caused slow response and overheated friction surfaces.Full scale laboratory testing in a D7E track-type Tractor setup was conducted. Oil formulations with poor field performance gave the same relative results in the laboratory test work.The Oil Test No. TO-2 was developed using the SAE No. 2 Friction Test Device. Correlation of the Oil Test No. TO-2 data with the full scale laboratory data is shown. Finally, reference oil data from the independent test laboratories using the Oil Test No. TO-2 is included to show the reproducibility and repeatability of the Oil Test No. TO-2.