Trajectory surface hopping calculations have been carried out for collisions of Ar++H-2 and Ar++HD on three low-lying potential energy surfaces projected from the original six in the Kuntz and Roach diatomics in molecules surface for this system. The location and probability of hops between surfaces were determined using the new algorithm developed by Parlant and Gislason. In addition to the reactive channel and total charge transfer to H-2(+) and HD+, dissociative channels to, for example, Ar++H+H, and Ar+H++H have been studied, Particular attention was paid to the dissociative charge transfer isotope effect for the processes Ar++HD-->Ar+H++D, or Ar+H+D+; near threshold the D+ product is favored over H+ which we attribute to preferential dissociation of excited ArD+ products. This is the first theoretical study of these dissociation processes.