Ford Focus Automatic Gear gave obvious sound like "tack" when changed gear between "P" and "R".

I would like to ask you about this issue for a week. This happened with my friend's car, Ford Focus Automatic Gear. While my friend changed Gear from "P" to "R", it had a sould like "tack" 1 time. Also when he changed from "R" to "P", it also gave him a same amazing sound "tack". The sound came from around the right-front wheel.

He just claimed the 2 front axle controllers for a few months. He could not guess the cause. Is it about the iron bullet in the wheels?

Gurus please help him.

Answer here or leave message at

Thank you,