Noisy Power steering/Brakes when Hot

[civilian]

Hi there, I'm new to the forum and also new to the world of Duramax
I Know this has probably been answered a few times but I haven't been able to find the answer. I have an 05 duramax After climbing a long hill (Initially I thought it was Altitude related) or pulling a 5th wheel for a while the Power steering and the brakes cause a loud whining noise from under the hood when either steering around corners or braking . Steering and Braking is not affected, they work fine, just noisy, and only while warm, The noise goes away very quickly when things cool down.
From what I've read the Hydro boost System causes the problem.
From some of the Forums I'v read the first try @ a cure is to Flush the System with Synthetic I Did That. (Used a gallon of fluid untill it was subtantially cleaner looking.) I may have helped a little but not much. Both the Brakes and the PS Whine when used.
So the next step is to start replacing parts I guess.
Question is : Do I replace the PS Pump or the Hydro boost Assy or do I have to replace Both?
Has anyone got any advice on the matter I would sure appreciate some help.
From what I've read in other Forums PS Pump replacement doesn't always cure the problem. It seems there are a few bad pumps out there ?

 

[btfarm]

I't's typical that a hydraulic system whine means a pump issue. Sometimes it's caused by air in the system rather than a bad pump. It can also be a valve sticking and makes the fluid 'whistle' through an undersized port.

 

[civilian]

Noisy Hydroboost

So You think most probably the PS pump is the cause? Braking and steering seem to be normal all the time , but something gets warm and starts to whine whenever the wheel is turned or the brakes applied . The noise doubles if you apply brakes going into a corner . PS pump looks fairly easy to replace but the other thing looks like a pain in the butt not to mention probably a lot more expensive. But the PS pump I can probably change myself.
As far as air in the system I think any possibility of that was taken care of with the Total flush. I ran a full gallon of fluid through that puppy.
Thanks for the quick response I'll change out the pump in the next few days and post the results.

I't's typical that a hydraulic system whine means a pump issue. Sometimes it's caused by air in the system rather than a bad pump. It can also be a valve sticking and makes the fluid 'whistle' through an undersized port.

 

[btfarm]

Hopefully that's it. Quite likely

 

[chevz7194]

Having the same problem. Flushed and added cooler with no help. Not sure what to replace next pump or hb?

 

[plowboy_lbz]

Mine does it too.