I have a 2010 F150 Lariat with 142000 miles. I have had issues with the power steering pump making noise. The dealer has replaced the pump, pulleys, hoses etc. In fact, last time I bought a used pump with only 40000 miles on it. The dealer installed it and it was quiet for a little while but now makes noise. They say they drained and flushed the system but it still makes noise. I am thinking that some fluid must stay in the system and then contaminates the pump. I don't know what to do anymore. Any one have any ideas? Thanks.