1998 Tahoe Just got it. Had a whine at 1500 and a leak at the pressure switch in back of pump. Through a reman pump and new seals in Switch (had some power steering above idle), no leak same whine. I knew this would be a waste of time but I know these boxes have problems. Put a box in, now I have a whine and zero power steering. I did do the bleed procedure several times. Heard the steering sensor could cause this but not feeling it. Pressure switches rarely go bad, What's up????