A heat exchanger module adapted for being mounted directly to the outer surface of the housing of an automobile system component, such as a transmission or engine housing, is provided. The heat exchanger module comprises a heat exchanger fixedly attached to an adapter module. The adapter module contains one of more fluid transfer channels, interface connectors, seals and mounting holes for screws and/or bolts. In one exemplary embodiment, the adapter module is comprised of an adapter plate that is sealed with one or more shim plates, the shim plates also providing a brazing surface for brazing the adapter module directly to the heat exchanger, the heat exchanger therefore being attached to the adapter module without the use of a base plate.