Mazda 6 Service Manual: No.21 noise occurs at idle when vehicle is stopped in d, s, l ranges, or in r position

No.20 noise occurs at idle when vehicle is stopped in all positions/ranges

No.22 no engine braking in hold mode

Other materials:

Mazda 6 Service Manual: Automatic transaxle fluid (atf) inspection
Automatic Transaxle Fluid (ATF) Condition Inspection One way of determining whether the transaxle should be disassembled is by noting: If the ATF is muddy or varnished. If the ATF smells strange or unusual. ATF Condition Automatic Transaxle Fluid (ATF) Level Inspection Caution Th ...

Mazda 6 Service Manual: Cruise Control (Some models)
With cruise control, you can set and automatically maintain any speed of more than about 25 km/h (16 mph). WARNING Do not use the cruise control under the following conditions: Using the cruise control under the following conditions is dangerous and could result in loss of vehicle control. ...