2000 Suburban Power Steering

My Suburban is a '00, 4WD, 5.3L K1500. Very hard if at all to turn left unless u accelerate or driving highway speeds. Turns right in any situation perfectly. Replaced pump 04/18/09, unhooked EVO on back of p/s pump to give full assist. Didn't help. This vehicle has a Steering gear, not a rack. I'm thinking gear replacement not the steering speed sensor(the one everyone calls the EVO and is on the column.) Because of what I've read here and other forums it doesn't have the symptoms that the steering speed sensor replacement is fixing. Any ideas!

Most likely this is a bad steering gear box. If it was the pump, it would be hard it both directions.

//2000CAYukon

Thank You much for your insight. I wish cars were like the old days. Just a pump and a gear. No sensors and selonoids. Got the gear today and now just got to put it on. Looks easier than the pump was I put on.