I have a 2006 Equinox lt and it makes a loud humming noise when I exceed above 40mph and also does it when I slow down from 55. Mph to till about 40mph. At slow speed absolutely fine .
Equinox 2006 LT
Mine is doing the same thing. I replaced the wheel bearings and it still does it. Did you figure it out?
Valve body in transmission, shift solenoids stuck giving low pressure in the gears or lock up converter, sometimes drives good... that's is the problem