Torque Converter Drainback Test
- Drive the vehicle for 30-60 minutes to attain normal operating temperature.
- Check the transmission fluid level. Add fluid only if required.
- Drive the vehicle through 8 to 10 cycles of 1/2 throttle, 1-2 upshifts to elevate the transmission temperature.
Then proceed as follows:
- Park the vehicle on level ground.
- Allow the vehicle to sit for 30-60 minutes.
- Check and note the fluid level on the fluid level indicator with the engine off, in PARK. The following example shows the fluid level after 45 minutes.
- Allow the vehicle to sit for a minimum of 24 hours. Check and note the fluid level.
- If the fluid has risen 25.4 mm (1 in) or more above the level in the first check, excessive converter drainback has occurred.
- If excessive drainback has occurred:
- stuck open check ball in rear cooler line case fitting.
- no check ball in rear cooler line case fitting.
- incorrect case cooler line case fitting (without check ball) installed.
- Service as required and recheck.