Checked the emergency brake cables underneath the truck. Pretty rusty & dirty. Sprayed some PB Blaster, let it sit & then sprayed some penetrant/lubricant. Did all this while the wife sat in the truck & moved the emergency brake handle up & down. Test drove a couple miles & no heat. Test drove a few more miles & it started to heat up. Again, only in the left rear wheel area. I think I will tear into the emergency brake on that side. If nothing is found I will try replacing the cable.