Abstract: A secondary drive unit (10) for demountable attachment to a machine having a primary drive unit and power take-off, the secondary drive unit (10) comprises a housing (12), a drivable input element (16) drivable by the machine at one end of the housing (12), a driven output element (18) at the other end of the housing (12) for driving a tool and/or another machine, and at least one rotatable gear carrier (44) in the housing (12) drivable by the drivable input element (16). An interior surface of the housing (12) includes a radially-inwardly projecting gear-carrier stop (58) overlapping the gear carrier (44). A low-friction rubbing element (62) is interposed between the gear-carrier stop (58) and the gear carrier (44) to prevent or limit gear-carrier lift. This prevents or limits undue lateral strain along a central rotational axis of the drive unit (10), and thus a possibility of internal shearing.

Abstract: A releasable auger tooth for an auger includes a slot shaped to fit a U-shaped or substantially U-shaped recess of a tooth holder element, and a tooth channel shaped to receive at least part of a shock-absorbing element and/or a wedging element. A holder element and assemblies are also provided.