I have posted about this growling noise in the power steering on startup since 2006. I searched my history and have 7 topics I've posted about this to try to resolve it. I finally got a knowledgeable tech from BAB steering and he assured me my pump was good and that somewhere there is a leak or another source of an air lock. I told him the reservoir location height is really close to the pump height, so I suggested I could raise it higher in the engine room. He thought that was a good idea, and he recommended a suction hose change that will not collapse. Also, T clamps only on that hose.
I moved the reservoir up high in the engine bay, found some Aeroquip type hose with a wire coil to make it stiff and T clamps. Relocated the hoses, tied everything tight and out of the way of the radiator fan, and refilled with ATF. The first engine run had lots of noise and took almost a gallon of ATF to get the system back to normal. The noise finally stopped after the system purged the air.
That was 2 weeks ago. Today was the first test. Started up the coach and oh my, no noise, no fluid blown overboard, no ATF all over my back end
Finally, something I tried worked. I hope I put this to rest for good. 13 years of this annoyance is too many.
Below is a picture of the relocated reservoir. It is about the same level of my radiator surge tank.
