Transmission fluid exchanger can gently clean dirt, varnish, sludge and other types of contaminants that build up in critical areas of the transmission system. In addition to fluid exchange, the unit can also be used to clean closed systems, flushing any impurities out of the pipes to support proper operation. The transmission flush machine features automatic flow control, automatic refrigerant refill, equivalent exchange, and recycle cleaning function to effectively change the oil by the power of the gearbox and the exchanger.