Using a model analytic potential energy function for Aln clusters [J. Chem. Phys. 1987, 87, 2205] and a UMP2(fc)/6-31G* potential derived here for the Ar---Al interaction, classical trajectory simulations are performed to study collision-induced dissociation (CID) of Al6 and Al13 with Argon. For the octahedral Al6 (Oh) cluster, the CID threshold is ~14 kcal/mol higher than the true threshold. This is because, near the threshold, there are no trajectories which transfer all the reactant relative translational energy to Al6 internal energy. For the planar Al6 (C2h) cluster, the CID threshold is closer to the true threshold. For the spherically shaped Al6 (Oh) and Al13 (D3d) clusters, T->V is the predominant energy transfer pathway. T->R energy transfer is important for the planar Al6 (C2h), Al13 (D2h), and Al13 (D6h) clusters. T->V energy transfer is enhanced as the cluster is softened (i.e., its vibrational frequencies lowered), the mass of the colliding atom is increased, and/or the relative velocity is increased. These effects are consistent with a previously derived impulsive model [J. Chem. Phys. 1970, 52, 5221], which says T->V energy transfer increases as the collisional adiabaticity parameter x is decreased.