Loss of power steering at low RPM?

[mtntruckin]

I just bought a 2001 2500 HD with the 6 liter gas motor, 5 speed manual, 124k miles. When I slow down for turns or stop signs, my tach idles at about 1k, then dips to 500. When it drops, I lose power steering until the RPMs gain back to a little over 1k, which makes tight turns in a big truck a little sketchy. No power steering whine, no leaks, nothin. Anyone have any idea what might be causing this? and how to fix? One theory I've been floating is dirty fuel injectors...gonna run a can of Sea Foam through the next tank of fuel and see what happens. Thoughts? Thanks!

 

[Molson02536]

I just bought a 2001 2500 HD with the 6 liter gas motor, 5 speed manual, 124k miles. When I slow down for turns or stop signs, my tach idles at about 1k, then dips to 500. When it drops, I lose power steering until the RPMs gain back to a little over 1k, which makes tight turns in a big truck a little sketchy. No power steering whine, no leaks, nothin. Anyone have any idea what might be causing this? and how to fix? One theory I've been floating is dirty fuel injectors...gonna run a can of Sea Foam through the next tank of fuel and see what happens. Thoughts? Thanks!

Your Sierra has hydroboost braking system, which uses power steering fluid to assist with braking, so it has a different design steering gear. Sometimes when a vehicle is built, there are inherent conditions due to slight variations in the design that cannot be changed. Engineering released the pressure control valve as a possible fix for some Sierra's. The GM trucks that was not helped has a slight pause in steering assist at very low engine rpm such as when backing, and then putting into drive, but when accelerating assist resumed.

Be aware that sometimes GM wil release service bulletins with updated info, so you may want to check in with the dealer from time to time, such as when having other service done. Replace the pressure control valve for the power steering rack/gear should address the issue.