If the pump is still noisy and the pressure is fluctuating, turn the Slide Kit adjustment 8 mm allen screw  clockwise 1/12 of a turn. This increases the pump pressure.
Caution: Only adjust in steps of 1/12 of a turn. Turning the Slide Kit adjustment screw too much can raise the pressure too high and cause damage.
Turn the pressure adjustment 5 mm allen screw  counterclockwise to reduce the pump pressure until the pressure is correct.
Note: The pressure should be approximately 450 psi for newer HPU's (without manifolds mounted on the tank lid) or 550 psi for older style HPU's.
Repeat this step if the pump is still noisy and the pressure is fluctuating until the noise has been eliminated and the pressure no longer fluctuates.
Record the approximate clockwise rotation of the Slide Kit adjustment screw  from its original position.
Tighten the hex jam nuts on both of the adjustment screws, reinstall the black cap, remove the pressure gauge from the pump outlet, make sure all fittings are tight, and return the bypass hose to the original routing if changed.