Seriously, whoever came up with these things needs to be forced to do fluid changes on them for the rest of their lives. Here is the procedure for a drain and fill on a GM 4T40, for your information. 1. Raise front of vehicle on ramps. 2. Remove a couple of pan bolts. 3. Fluid will start to spill everywhere, over an area much bigger than your drain pan. 4. Fluid will stop. Time to remove a few more bolts. 5. More fluid will spill everywhere, including on your face. 6. Fluid will stop. Remove the last few bolts. 7. Pan will fall. Fluid will spill everywhere. 8. Clean pan. Alcohol and paper towels work well, and are fun to light on fire afterwards! 9. Drill a %#*! hole and install a %#*! drain plug in the back of the pan so you make less of a mess next time. 10. Install a new gasket, bolt pan back up to transmission. 11. Remove fill plug from top of transmission. 12. Drop fill plug behind transmission. 13. Reach back there to grab fill plug. Instead, manage to knock it into the abyss where it will likely never be found again. 14. @#%! it, I'll deal with that later. Beer. 15. Remove intake to make room for long funnel to fill the transmission. 16. Add a gallon of fluid. 17. Notice new trans filter still sitting on passenger seat. 18. Sigh. Beer. 19. Remove drain plug. See, that's already coming in helpful. Drain fresh fluid back into the jug I poured it from. 20. Drop pan. Spill residual fluid everywhere. 21. Remove filter. Spill more fluid everywhere. 22. Install new filter. 23. Re-install pan again. 24. Add gallon of fresh fluid back into transmission. 25. Jack up the rear of the car. Front is on ramps, and my service manual makes very clear that it must be level for the fluid level to be correct. 26. Turn the engine on. 27. Idle for 5 minutes. 28. Move the shifter through all the gears, while the car is on a combination of ramps and jack stands. Because that's safe! 29. Attempt to remove check plug from side of transmission. Did I mention it's right next to the exhaust, which is hot because the car must be running to do this. 30. Burn hand on exhaust. 31. Beer. 32. Successfully remove check plug. No fluid comes out. 33. Pour in another gallon. Fluid slowly starts to trickle out, flowing down various crevices and crannies and totally avoiding my drain pan again. 34. Re-install check plug. 35. Burn hand on exhaust. 36. Stuff a rag in the fill hole and I'll deal with that later. A new fill plug is $11 online, so I'll probably grab one from the junkyard for a buck or two later this week. Don't need the car until then. EDIT: Drained out what was most likely Super Tech Dex 3 from ~10 years and 60k miles ago. Fluid was dark, but still smelled sweet (oddly I like the smell of ATF...) not burnt, and there was virtually nothing on the pan. No pics of tranny porn (wow that came out wrong!) but I did get one of the drain plug. M12 nut, plug, and fiber washer from Ace, total cost $3 and change.