Hi, I’m a Navy Diesel Mechanic used to working on engines the size of my truck and am getting beat up by a power steering problem. The truck is a 03 Sierra Z71 5.3L with 180K miles. First I don’t have the Y91 Option which I believe includes the EVO valve everyone is talking about. It also doesn’t have vacuum assisted steering. The truck steers fine in both directions if you are moving above parking lot speed. If you are moving slow or stopped and turn the wheel from straight to right or right to straight it’s fine. If you turn the wheel from straight to left it’s like there is no power assist at all. You can also hear a loud hissing sound. I lifted the front of the truck so both wheels were off of the ground. With the engine running or off the steering wheel turns freely through the entire range of motion. You can also rotate the steering wheel through the entire range of motion by moving the tires back and forth by hand. There is no binding in the steering system at all. I think it’s either the pump or steering box. Then I think it’s not the pump because the truck turns fine from straight to right or right to straight. The pump does not know which direction you are turning. Also, with the truck in park and the engine at 1000-1500 rpm simulating driving it’s still hard to turn the wheel left. So increasing pump rpm does not help the problem. Only actual truck movement allows movement of the wheel to the left. I’m thinking it’s the steering box. What do you think.
Friday, February 24th, 2012 AT 4:22 PM