
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.

WARNING
Do not use sudden engine braking on slippery road surfaces or at high speeds:
Shifting down while driving on wet, snowy, or frozen roads, or while driving at high speeds causes sudden engine braking, which is dangerous. The sudden change in tire speed could cause the tires to skid. This could lead to loss of vehicle control and an accident.
Always leave the shift lever in 1 or R position and set the parking brake when leaving the vehicle unattended:
Otherwise the vehicle could move and cause an accident.
CAUTION
NOTE
If shifting to R is difficult, shift back into neutral, release the clutch pedal, and try again.
Gear Shift Indicator (GSI)Mazda 6 Owners Manual: Instrument cluster removal/installation
Caution
When replacing the instrument cluster, the configuration procedure must be
performed before removing the instrument cluster. If the configuration procedure
is not performed before removing the instrument cluster, it is possible that the
instrument cluster will not operate normally. ...
Mazda 6 Owners Manual: Drive shaft (mtx) disassembly/assembly
1. Disassemble in the order indicated in the table.
2. Assemble in the reverse order of disassembly.
Clip Disassembly Note
1. Mark the drive shaft and outer ring for proper assembly.
Caution
Mark with paint; do not use a punch.
2. Remove the clip.
Balls, Inner Ring, Cage Disassembl ...