I know it's not a truck but.....I am working on a 2001 Mustang with a 3.8 V6. It is whinning like crazy. Sounds like a bad power steering pump. I tracked the noise down to the A/C compressor. I replaced that and it's still whinning. I also replaced the power steering pump, and the water pump. The noise is comming from the passenger side of the car. Any ideas?? The A/C pump was replaced with a compressor from a bone yard.........HELP!!!!!!!!!!!!!!!!