Mazda 6 Service Manual: No.9 abnormal shifting

No.8 does not shift to fourth gear (4gr)

No.10 frequent shifting

Other materials:

Mazda 6 Service Manual: Driving on Uneven Road
Your vehicle's suspension and underbody can be damaged if driven on rough/uneven roads or over speed bumps at excessive speeds. Use care and reduce speed when traveling on rough/uneven roads or over speed bumps. Use care not to damage the vehicle's underbody, bumpers or muffler(s) when driving ...

Mazda 6 Service Manual: Dtc c1955, c1956
Caution When attaching the tester lead to the DSC HU/CM connector the SST (49 G066 004) must be used. Diagnostic procedure ...