Power Steering/hydroboost Issue

[stonedigity]

Ok fellas, here's the deal. The truck is an 05 1500HD 6.0L/4L80E with 3:73's and 285/75-16 tires with a Wait4MePerformance tune. This last weekend I was towing a 6500-7000 lb trailer up a long 6% grade. Felt real heavy. It dropped into 2nd and was at ~4k rpm doing about 50mph. After cresting the hill, I got on the brakes and got a NASTY power steering whine. Brakes and steering felt fine. Stopped, no leaks, opened the cap and fluid level looked a bit high. Put the cap back and kept going. Noise went away, but came back later but not nearly as bad.

 

I'm gonna do a synthetic PS flush (I'm thinking air in the system), but anything else to consider?

[masterp2]

I am assuming you don't have a cooler?

 

Many of these trucks don't have a PS cooler, and this can make the fluid really heat up.

[stonedigity]

No cooler on the power steering. For such a cheap mod, I'm going to install one for sure. Has anyone else experienced anything like this?

[masterp2]

...It dropped into 2nd and was at ~4k rpm

 

 

My personal thought is that it heated up with the high rpm (full hi flow bypass=heat), and you experienced cavitation with the flow demand of hitting the brakes.

 

I have been doing some research work over the past few weeks, and when I saw that even 1 ton trucks with hydroboost don't have a cooler, my jaw dropped.

[trask]

I had the same experience last year with my 04 HD2500 truck in hot weather and it has a power steering cooler, I had the power steering system flushed and replaced with synthetic oil but it still is pretty noisy when the temp. goes up. I may look into getting a different cooler.