Torque Converter Drainback Test
Torque Converter Drainback Test1. Drive the vehicle for 30-60 minutes to attain normal operating temperature.
2. Check the transmission fluid level. Add fluid only if required.
3. 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.
4. Allow the vehicle to sit for a minimum of 24 hours. Check and note the fluid level.
5. If the fluid has risen 25.4 mm (1 inch) or more above the level in the first check, excessive converter drainback has occurred.
6. 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.
7. Service as required and recheck.