  We offer a general approach to calculation of single-electron tunneling
spectra and conductance of a shuttle oscillating between two half-metallic
leads with fully spin polarized carriers. In this case the spin-flip processes
are completely suppressed and the problem may be solved by means of canonical
transformation, where the adiabatic component of the tunnel transparency is
found exactly, whereas the non-adiabatic corrections can be taken into account
perturbatively. Time-dependent corrections to the tunnel conductance of moving
shuttle become noticeable at finite bias in the vicinity of the even/odd
occupation boundary at the Coulomb diamond diagram.
