Allison Transmission Questions Hi baja, Sure you can perform your own service and flush yourself. 1. Remove drainplug and drain fluid. 2. Remove pan and save gasket because it is re-usable 3. Drain and clean pan 4. Re-install pan and torque bolts to 20 ft.lbs.Internal filter change is not neccessary only at overhaul. 5. Change external filter 6. Add approx. 4 gals. Transynde 7. Remove cooler return line from transmission (one with arrow pointing towards transmission) 8. Have someone start transmission and let approx 1 gal. oil come out of the cooler return line into a bucket.Then tell person to shut off truck. 9. Re-install line onto transmission. 10. Adjust oil to correct level 140 deg F Just keep these instructions and warranty should be no problem if you do on your own. Thanks for the ? and have a great day!