  We report the results of dynamical simulations, covering Gyr timescales, of
fictitious Scattered Disk Objects as a follow-up to an earlier study by
Fern\'andez et al. (2004: {\it Icarus} {\bf 172}, 372). Our dynamical model is
similar in that it does not include external agents like passing stars or the
Galactic tide. Only the four giant planets are explicitly treated as
perturbers. We analyze the random-walk behaviour of the inverse semi-major axis
by means of a simplified circular restricted 3-body problem as an approximate
analogue. Our results concerning the role of resonant effects and the transfer
efficiency into the orbital energy domain of the inner Oort Cloud are in broad
agreement with the earlier papers, and we confirm the important role of
external objects (with perihelia beyond Neptune's orbit) in feeding the Oort
Cloud. We estimate the efficiency of this transfer to be even somewhat higher
than previously found.
