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: Rocking the Vehicle
WARNING Do not spin the wheels at more than 56 km/h (35 mph), and do not allow anyone to stand behind a wheel when pushing the vehicle: When the vehicle is stuck, spinning the wheels at high speed is dangerous. The spinning tire could overheat and explode. This could cause serious injuries. ...

Mazda 6 Service Manual: Recommendations for Shifting
Upshifting For normal acceleration, Mazda recommends these shift points: For cruising, Mazda recommends these shift points: Downshifting When you must slow down in heavy traffic or on a steep upgrade, downshift before the engine starts to overwork. This reduces the chance of stalling and ...