This V-belt transmits power from the engine to the hydraulic pump assembly. It sits in the threshing mechanism drive, connecting the crankshaft pulley to the pump input pulley. A worn or slipping belt reduces hydraulic flow, causing sluggish implement response and potential overheating of the pump drive. The manufacturer machines the belt to match the original cross-section and length, ensuring correct tension without over-tightening the idler pulley. On replacement, verify the belt sits fully in the pulley grooves and adjust the tensioner to the specified deflection.