2002 Chevy Silverado front wheel/CV joints

I have a '02 K-1500 Silverado with 100,000+ miles. I notice a loud humming at highway speeds that seems to be coming from the left front wheel. I took the wheels and the brakes off and spun the half shafts by hand, but can't find any tell tale signs of a bad bearing or CV joint. I purposely disassembled it before everything had a chance to cool off, hoping to find something too hot to touch, but didn't. The left side is a little harder to turn than the right, and there is a slight racheting sound coming from the transaxle, but not loud enough to concern me. I replaced the brakes (rotors and pads) less than 2000 miles ago and am confident the problem isn't in the brakes.
Has anyone had similar experiences? Thank You