Mazda 6 Service Manual: No.7 no shifting

No.6 low maximum speed and poor acceleration no.7 no shifting

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

Other materials:

Mazda 6 Service Manual: Intermittent concern troubleshooting
  Vibration Method 1. If malfunction occurs or becomes worse while driving on a rough road or when engine is vibrating, perform the steps below. Note There are several reasons vehicle or engine vibration could cause an electrical malfunction. Some of the things to check for are: ...

Mazda 6 Service 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 ...