Determine your axial and torsional loads:

Mt calc = Calculated torque with Sm service factor (lbs-ft)
Mt cat = Catalog rating of ETB35a
Pax = Axial load/thrust to be transmitted (lbs)
d = Shaft diameter (inches)
Ps = Pressure applied to shaft (psi) by ETB35a
Ph = Pressure applied to hub (psi) by ETB35a