For those using an LS engine w/ hydraboost brake p/s pump: 2 ret port pump] There is a chance the pump will be noisy due to cavitation, if the return from the p/s gear is hooked to the top port. I have found other instances that this is the cause, as well as have this problem on the 6.0 in my 55...I found it too late, as I had already changed the pump. Others have succeeded in just moving the line...
