Abstract: A converter allows a user to convert a conventional car jack from a non-specialized, general service variety into a specialty transmission jack. The car jack has a low, wheeled frame; a handle; a boom extending between a base end pivoted to the frame near the handle and an opposite end formed with a seat portion; and a hydraulic cylinder stretching between the frame and the boom which is actuated by pumping the jack handle to raise the boom. The seat portion of the boom is formed with a socket. The car jack conventionally is provided with a conventional cup having a stem which allows removable seating in the socket of the jack's boom. The converter head has a base plate defining a plane; a stem beneath the base plate for removable seating in the socket of the jack's boom; four or so arms extending between a butt end and a tip end; and cap screws threaded through the tip end of each arm. The cap screws allow adjustment in length and provide upper contact ends for propping a vehicle transmission thereon.