When I hit the brakes real hard, I don't feel a pulse like in my other cars. I feel something in the brake pedal, like ABS is kicking in, but sounds like a loud humming sound. Just had the front and rear pads replaced and rotors turned, about 2 or 3 hundred miles ago. Brakes also feel a little squishy, like I couldn't stop on a dime if I had to. I know it's a heavy truck, but is that normal?