Automatic Transmission Fluid Flush
ATF flush / change procedure
Step 1: Remove the bash plate
- Remove the single bash plate under the transmission, using a 14mm spanner/socket.
- Clean the pan, paying particular attention to the drain, overflow and fill plug locations. Also wipe over the driveshaft, to prevent contamination, as the fill line will run over it.
Step 2: Drain and Refill the pan
- Using a 24mm socket, loosen the refill plug located on the left side of the transmission.
- Position a clear, 4-5 litre graduated container under the drain hole, remove the drain plug (14mm), and drain the pan into the jug. Note how much oil has been drained, which should be approximately 3.1 litres. Empty the jug into a waste oil container. You'll need it again in step 3.
- Re-insert the drain plug and tighten to 20Nm (reuse the original crush washer at this stage. It will be replaced later).
- Fill a clean graduated jug with the same amount of fresh fluid as you drained from the pan.
- Remove the refill plug, and using a 12v pump or hand pump, refill the transmission with the fresh fluid.
Step 3: Flush the oil cooler and lines
- (a) Disconnect the rubber hose from the oil cooler return line on the side of the transmission. It is the upper of the two lines (see photo). Ensure you wipe clean the lines before disconnecting the rubber hose.
- (b) Attach a clear tube to the metal oil return line, and run it to your clear graduated drain container, placed beside the car where you can see it from the drivers' seat.
- (c) Start the engine, and as it idles, slowly move the gear lever through all the gears (P, R, N, D, 1-6). Keep doing this until 1.7 litres of fluid has been pumped out into the clear container, then turn off the engine.
- (d) Refill 1.7 litres of fresh fluid into the transmission via the refill hole.
- (e) Dispose of the used fluid into the waste oil container.
- (f) REPEAT steps (c) to (e) two more times.
- At this point, you should have around 3.8 litres of new fluid remaining (sufficient for one more full pan drain), having drained and replaced 8.2 litres of fluid in total:
- 3.1 litres from the pan;
- 1.7 litres from cooler line;
- 1.7 litres from cooler line;
- 1.7 litres from cooler line.
- Now, remove the clear tube from the oil return line, reconnect the original rubber hose and replace the hose clamp.
Step 4: Drive and final pan drain
- Ensure the drain and refill plugs are suitably tensioned, and the oil cooler lines are re-attached and clamped.
- Take the car for a short drive, preferably somewhere where you can engage and drive in every gear. Allow the vehicle to cool for an hour when you return, to prevent burns from the hot exhaust and/or transmission fluid.
- As with Step 2, loosen the refill plug, remove the drain plug and drain all the oil from the pan into the clear graduated drain container.
- Refit the drain plug using a new crush washer, and tension it to 20Nm.
- Refill the transmission with slightly more fluid than was drained. 100-200ml should do it. This excess (if there is any) will be drained off in the next step.
- Replace the fill plug (using a new O ring) and tension to 39Nm.
Step 5: Ensure you have the correct fluid level at operating temperature.
At this point, the transmission fluid should be just above 'overflow' level. However, the fluid level must be checked at between 41 and 46ºC.
If you have an Ultragauge or Scangauge, you can use that device to show the ATF (pan) temperature. If you don't have one, then you must follow the following procedure to enable the in-built temperature indicator:
- Connect a wire between pins 4 and 13 of the OBDII connector, located below the steering column.
- Slowly move the shift lever from P to S, then change the gears from 1st to 6th. Then return the shift lever to P.
- Move the shift lever to D, and quickly move back and forth between N and D (at least every 1.5 seconds) for at least 6 seconds. This will activate the fluid temperature detection mode.
- Return the shift lever to P and disconnect the wire joining the OBDII terminals.
- Allow the engine to idle until the fluid temperature reaches 41 to 46°C
- Even though the vehicle is in Park, the D indicator will come on again (so both P and D indicators will be illuminated) when the fluid temperature reaches 41-46°C. If you have an Optitron display (VX, Sahara), then the gear position indicator will change from P to D when the temperature is correct. If the D indicator flashes on either type of dash display, then the ATF temperature has exceeded 46ºC. You'll have to switch off the car and allow it to cool. On a warm day, this could take a couple of hours.
Once the Ultragauge/Scangauge or the inbuilt sensor detects the transmission is between 41 and 46ºC:
With the engine running, A/C turned off, and the transmission in Park:
- Remove the overflow plug. Allow the excess fluid to overflow until it's just a slight trickle.
- Fit a new crush washer, and replace/tension the overflow plug to 20Nm.
- If the fluid did not overflow, add more fluid until it does overflow. Watch out for the hot exhaust. Refit the refill plug (with a new O ring).
As you can see from the above photo, the transmission fluid was very dirty/dark at the beginning of the flush, but became progressively cleaner as the changeover progressed. The fluid was changed at around 100,000km.
After the change, there was a small improvement in shift quality, but no other changes were apparent.