This hydraulic motor drives the cutterbar on the parent combine header. It converts hydraulic flow from the machine's pump into rotary motion that powers the reciprocating knife assembly. The motor mounts at the side of the header and connects directly to the drive mechanism that moves the knife sections. Wear in the motor's internal seals reduces cutterbar speed, leading to uneven crop cutting and increased load on the hydraulic circuit. As an original component, the motor matches the mounting flange pattern and shaft dimensions of the assembly it replaces, so no adapter plates or shaft modifications are needed.