Rotary cutter troubles

[jbird5986]

Hey guys Im trying to frankenstein a bush hog together and the 75 hp. gear box I would like to use wont turn the blade unless you push in on the input shaft.My question is are there clutches in there or something?The 35 horse gearbox just turns normal.I think maybe its bad but I know nothing about them.The 35 will mount up to the frame im using but blades are short is it safe to get longer blades?There isnt alott online about turning 5 bush hoggs into 1. Thanks

 

[Firebrick43]

Many have shear pins, some have clutches but the ones I have seen sit outside the gearbox, I have not seen one yet with it in the gearbox.

Either way, the shaft shouldn't have to be pushed in to engage. You shouldn't be able to push it in period. You have a failed input quill bearing and you probably have gear issues as well due to the failure of the quill.