Gearbox guides

• Aisin EAT8 8-speed automatic (Peugeot, Opel, Citroen): problems, costs and what to check

  A smooth 8-speed that lasts when its oil is changed. Buy with fluid records and a clean scan, avoid one that judders or has been in limp mode.

• Audi DL382 7-speed S tronic (0CK): problems, costs and what to check

  A smooth gearbox when serviced, but mechatronic and clutch bills are large, so buy only with a scan and oil records.

• Mercedes 7G-DCT dual-clutch (724.0): problems, costs and what to check

  Smooth when serviced, but early cars judder and mechatronic or clutch repairs are costly. Buy on oil history and a cold test drive.

• Mercedes 7G-Tronic (722.9) 7-speed automatic: problems, costs and what to check

  Buy only with fluid records and a clean full-system scan, and avoid any car that has run in limp mode or judders at a steady speed.

• VW DQ200 7-speed DSG (0AM, 0CW): problems, costs and what to check

  Dry DSG with a known weak mechatronic and clutch. Buy only with recall and oil-change records and a clean pump test.

• VW DQ381 7-speed wet DSG (0GC): problems, costs and what to check

  Wet DSG with weak mechatronic pressure sensors, so buy only with a scan, a hot test drive and oil service records.

• ZF 6HP 6-speed automatic (BMW Steptronic, Audi tiptronic): problems, costs and what to check

  A workable six-speed when its fluid is changed on time, but mechatronic and bushing wear recur. Buy with service proof and a clean scan.

• ZF 8HP 8-speed automatic (BMW Steptronic): problems, costs and what to check

  A solid 8-speed when its fluid is changed on time. Buy with oil records and a clean scan, and avoid one that shudders or has run in limp mode.