See "Torque Taper Plus Helical Shaft Mount Speed Reducers Installation Maintenance Manual" Form 8780-A (hereafter referred to as "TTP Maintenance Manual"). Note after paragraph 2.1.5. However, if the torque arm must be used in compression, it is recommended that the angle between the torque arm and a line through the hollow output shaft and the center of the torque arm bracket should be 90 +/- 5 degrees.