I have a 2004 Pontiac Grand Prix GT. I have already changed the power steering pump three times and it still wines. I have used Lucas power steering conditioner and it only quieted temporarily for 3 months. I need to know if I have another dud power steering pump or just need a new racket and pinion steering with magnasteer? By te way, the first 2 power steering pumps were purchased at Autozone. My third power steering pump was purchased at Oreilys. Someone please help me.