A power steering gear for a heavy vehicle includes a housing and a flow path for a power steering fluid. A heat exchanger is mounted to the housing or is a part thereof. The heat exchanger includes a first flow path for the power steering fluid and a second flow path for a coolant adapted to exchange heat with the power steering fluid. A cooling system for a power steering gear, a heavy vehicle comprising a power steering gear having such a cooling system, and a method of cooling the power steering fluid of a power steering gear on a heavy vehicle are also disclosed.