  The low temperature properties of single level molecular quantum dots
including both, electron-electron and electron-vibration interactions, are
theoretically investigated. The calculated differential conductance in the
Kondo regime exhibits not only the zero bias anomaly but also side peaks
located at bias voltages which coincide with multiples of the energy of
vibronic mode $V \sim \hbar\Omega/e$. We obtain that the evolution with
temperature of the two main satellite conductance peaks follows the
corresponding one of the Kondo peak when $\hbar\Omega \gg k_B T_K$, being $
T_K$ the Kondo temperature, in agreement with recent transport measurements in
molecular junctions. However, we find that this is no longer valid when $
\hbar\Omega$ is of the order of a few times $k_B T_K$.
