Volvo Construction Equipment is a world leading company in construction machinery. Tomaintain the best products, development is prioritized. The master thesis regards sound reductionof the hydraulic system on a wheel loader. The background to the master thesis is asimulation made on the hydraulic system, performed autumn 2005. The result of the simulationshows that the energy of the pressure ripple is reduced when the paralleled hydraulicpumps are phase shifted and reduces each others pump pulsations.