The key component for huge pulling power on PTO driven winches is the clutch packs. All the pulling power for these winches in transferred to the drum through the clutches. Proper installation and cooling for these components is critical for the life of the winch and proper performance. On the Allied W6F clutch shaft you can see that one of the splines must line up perfectly with a the adjacent spline on the hub with a dowel pin. We've found the easiest way to install the clutch shaft is with the winch on it's side. Please give us a call if you have any questions.