Check / Replace AF40 Transmission Fluid

Transmission Fluid Level, Check and Correct (AF40 – Vectra C, Signum)

Important:  The following operation has two procedures:

A. Prefill transmission fluid with the engine off, after repair work on the transmission, removal and installation / replacement of gearbox or axle shafts. After prefilling with the engine off, the transmission fluid level must be checked with the engine running. (steps 1 to 7)

B. Check transmission fluid level and correct with engine running.  (Steps 8 to 11)

Note: The fluid level must only be checked in conjunction with the fluid temperature, see TECH 2, after work or fluid loss, and corrected if necessary. Ensure that only the correct transmission fluid for AF40 is used.

This gearbox is otherwise known by its manufacturer’s name, Aisin TF-80SC and the fluid specified has to be AW-1.  The Vauxhall fluid is part no 93 165 147 in 1 litre bottles and you will need 4 litres for a simple fluid change and about 8 litres for a full fluid change.  The full capacity of the gearbox is 7.2 litres, however you may only be able to remove approximately 3 litres because the torque converter contains the rest and doesn’t drain.  Thus to carry out a full change of the fluid (and not just half of it!) it is necessary to flush the transmission oil (preferable) or carry out at least 4 drain and fill cycles to get 80% of the fluid out.  Vauxhall TIS suggests it is possible to drain half the contents of the torque converter by allowing the transmission to drain overnight.  I have tried this and it didn’t happen.


1. Test conditions:

  • Vehicle must be standing on a level surface
  • Selector lever in position “P
  • Engine OFF
  • Connect TECH 2 and delete fault memoryAF40 filling bolt

2. Unscrew fluid filling bolt (1) which is a T50 Torx plug on the top face of the gearbox towards the rear.

Important: If the transmission fluid level is only to be checked, skip to Work Step 8.

3.  Prefill transmission fluid when changing gearbox and after repair work – engine off

  • Place collecting pan underneath.

Important: The rising tube (3) must not be unscrewed to check the fluid level. With the fluid checking bolt unscrewed, the fluid will run AF40 drain bolt and level tubeout of the rising tube to the fluid level (6) at the upper edge of the rising tube.
The rising tube must only be unscrewed to drain the transmission (1). In this case, replace the seal (2) on the rising tube.

4. Unscrew fluid checking bolt (5) from rising tube
Note: Renew O-ring (4).

5. Add ATF until it drips out of the rising tube

6. Tighten fluid monitoring bolt 8 Nm

7. Top up ATF – pour into fluid filler hole

  • Top up with 0.5 litres of ATF

Important: The transmission fluid level must be checked correctly with the engine running and transmission fluid temperature 70° to 80°C.

8. Check transmission fluid level and correct with engine running.

9. Start the engine

10. With the footbrake actuated, shift through the selector lever positions

  • Shift selector lever from position “P” to “D” and back to “P”, maintaining each position at least 2 seconds and repeat this process twice
  • Check transmission fluid level with TECH2 (see data list parameters)

– Unscrew fluid checking bolt

– Allow transmission fluid to drain until it drips out of the rising tube, otherwise top up transmission fluid until it drips out of the rising tube.

– Tighten fluid check bolt with new O-ring 8 Nm

– Fill with 0.5 litres of ATF

– Switch off engine

11. Tighten fluid filler bolt with new seal ring 40 Nm

And that’s it, I think you’re done. 🙂