Originally Posted by bob919

Swore my whine was the PS pump going bad. Drove it for 4 years that way and finally decided to fix it.

Did all the things mentioned in this thread staring with the cheapest fix first: 1. flush/change the fluid and cleaned the screen in the reservoir; 2. rebuilt PS pump using the Gates rebuild kit; 3. replaced AC idler pulley; and finally 4. purchased a remanufactured PS from RockAuto. None of the "fixes" solved the problem. Whine was still there.

Finally took advice from an old mechanic friend of mine long gone: used long screwdriver and put it on the alternator and other end to my ear and sure enough, could hear it whining and "grinding". Bearings were bad.

Installed Denso remanufactured from RockAuto and whine is gone! Changed out all 3 belts while at it. Swear truck runs better now than it has in years.

So don't rule out the alternator bearings as the issue.