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: Manual Transaxle Shift Pattern
  The shift pattern of the transaxle is conventional, as shown. Depress the clutch pedal all the way down while shifting; then release it slowly. Your vehicle is equipped with a device to prevent shifting to R (reverse) by mistake. Push the shift lever downward and shift to R.   ...

Mazda 6 Service Manual: Abs (abs/tcs) hu/cm removal/installation
Caution When replacing the ABS (ABS/TCS) HU/CM, configuration procedure must be done before removing the ABS (ABS/TCS) HU/CM. If configuration is not completed before removing the ABS (ABS/TCS) HU/CM, TCS will not work properly (with TCS model). Do not drop the ABS (ABS/TCS) HU/CM. Re ...