Abstract: A hydraulic driving mechanism for a vehicle wheel includes a housing and three piston-cylinder assemblies pivoted to side plates of the housing. Each assembly communicates with hydraulic fluid under pressure and a reciprocating piston rod of each assembly drives a pinion through a surrounding eccentric and driving ring when the assembly is rocked in an arc about its pivot connection. The assemblies and corresponding pinions are located around and in mesh with the outer periphery of a central pinion which is affixed to an output shaft to rotate the wheel. The rocking of each assembly causes a sliding valve within a control valve housing to open and close return and inlet fluid ducts. An anchorage links each sliding valve to the housing for the mechanism. The housing affords the connection between the wheel and the vehicle frame and includes two spaced-apart plates with strips between the plates that leave upper and lower blocks.