All of it. The 10 percent figure you occasionally see is nonsense that a lot of people believe just because they've seen it so much.
Quick Answer. Some things that cause a vehicle's front end to make a clunking noise are worn ball joints, a damaged tie rod, broken or loose sway-bar links, hard or damaged shocks, and faulty shock mounts. An automotive professional can inspect the vehicle's front end to locate the source of the clunk. Continue Reading.
#2. The sound you are probably hearing is straight-cut transmission. The whining noise is caused by the teeth of the gears slamming together. Its nothing to worry about and the reason why it's not audible in most road cars is that they use helical gears to keep the transmission whine to a minimum.