From a numerical solution of the time-dependent Schrodinger equation and the lattice equation of motion we obtain a microscopic picture of polaron transport in highly ordered molecular crystals in the presence of an external electric field. We have chosen the pentacene single crystal as a model system, but study the transport as a function of the intermolecular interaction strength, J. We observe a smooth transition from a nonadiabatic to an adiabatic polaronic drift process over the regime 20 < J < 120 meV. For intermolecular interaction strengths above similar to 120 meV the polaron is no longer stable and the transport becomes band like. (c) 2006 Elsevier B.V.. All rights reserved.