Mazda 6 Service Manual: No.20 noise occurs at idle when vehicle is stopped in all positions/ranges

No.19 excessive shift shock on torque converter clutch (tcc)

No.21 noise occurs at idle when vehicle is stopped in d, s, l ranges, or in r position

Other materials:

Mazda 6 Service Manual: Inspecting Coolant Level
WARNING Do not use a match or live flame in the engine compartment. DO NOT ADD COOLANT WHEN THE ENGINE IS HOT: A hot engine is dangerous. If the engine has been running, parts of the engine compartment can become very hot. You could be burned. Carefully inspect the engine coolant in the coola ...

Mazda 6 Service Manual: Automatic Transaxle Controls
Various Lockouts: Indicates that you must depress the brake pedal and hold in the lock-release button to shift (The ignition must be switched ON). Indicates the shift lever can be shifted freely into any position. Indicates that you must hold in the lock-release button to shift. N ...