Abstract: In one aspect of this invention, a system and process for controlling a fluid actuated retarder is disclosed. This includes an input mechanism and an electronic controller for receiving a signal from the input mechanism, including a value for a desired retarder control level. Also, there is a proportional solenoid valve that is actuated by the electronic controller. The proportional solenoid control valve is operatively connected to a proportional retarder spool valve and the proportional retarder spool valve is operatively connected to a fluid actuated retarder.

Abstract: Apparatus for automatically determining the total sound power emitted by a work machine. The noise testing system employs a processor and remote control to control the measurement of both exterior and interior sound generated by a work machine in either a dynamic or static operating mode.