braking while going over bump. ABS quirk?

I'm wondering if this is a behavior of the ABS... when going over a bump at high speed and with the brakes applied, I can feel a motor spooling thru the floorboard. Sensation lasts for about 2 seconds.. Sometimes, I can hear it too if road noise is not too loud. Wondering if this the ABS activating...

 

Sounds like it to me...ABS feels like rapid clunking and happens when your wheels get airborne and lock up.

 

Right.. I'm familiar of how the ABS feels when the wheel is slipping when braking at low speeds..

However, this feels different.. when the bump is large enough, after I pass over the bump, I can feel this motor spooling...

 

I think I know what you're talking about... It's like after mine lock up and the ABS starts pumping them, when I finally come to a stop and the ABS stops pumping the brakes, I can still hear something running, sounds almost like a very muffled sander running. It's like it's just coasting to a stop and I hear it for about half a second. I'm assuming it's normal. Mine also activates when the front wheels go airborne under braking.