2008 Chevy Trailblazer SS “ah-ooo-ga”-like sound coming from brakes

My Trailblazer SS makes a sound that is almost exactly
like an “ah-ooo-ga” horn when you’re moving and press  
the brakes down to come to a stop. Only when you’re
moving though. Not when in reverse or sitting still.
Something with the ABS was repaired/replaced a year ago
so I don’t know if that could be it. But the ABS light
doesn’t come on when it happens, steering doesn’t
change and the brake pedal doesn’t change. ANYONE
have any idea what it could be