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: Rear door lock actuator inspection
Door Lock Actuator 1. Disconnect the front door lock actuator connector. 2. Apply battery positive voltage to the front door lock actuator terminals and inspect the operation of the front door lock actuator. If not as specified, replace the front door lock actuator. With double locking ...

Mazda 6 Service Manual: Solenoid valve removal/installation
1. Disconnect the negative battery cable. 2. Remove the under cover. 3. Remove the control valve body. (See CONTROL VALVE BODY REMOVAL.) 4. Remove the solenoid valve(s). 5. Apply ATF to a new O-ring and install it on the solenoid valve. 6. Install the solenoid valve in the control valve body. ...