Ursus4011 wrote: I don't know, I will ask ... Is there a wedge that blocks this wheel ???
If the wheel on the transmission spins "together with the axle" then either, as I wrote, damaged modes or claw clutch / engagement does not work, in other words damaged transmission. The pulley itself, at the transmission, is "stiffened" on the axle by a wedge, prismatic groove, size 6x6x20, but there is too little force to "cut", as I wrote the most common cause of failure in these spreaders is damage to modes in the transmission or claw coupling, drive switch. In the link I gave you is the instructions with the parts catalog and there everything is given with even the smallest washer as it is built.