That's somewhat normal if the car wants to move forward (downhill or engine applying power).
Definitely somewhat normal especially if it's a somewhat older vehicle.
I have two cars that can do this. its a result of friction and low vibrations as brake are binding but allowing wheel or brake pad surface to move . very much like sliding our hand hard over some surfaces ..we get a shudder as surfaces slip and immediately grip then slip again rapidly. think of trying to slide our plan over a wet glazed plate and putting heavy pressure at same time to grip it. it grips..then slip..then grips.
so our moaning etc is same thing but mechanically produced.
its only a worry if it occurs when applying brakes as normal.. then its often a case of very worn pads or shoes.
have your brakes checked
This only happens as I am slowly releasing the brakes. It doesn't happen when I press down on the brakes for a full stop; only whenever I slowly release them.
