Drainplug_fan

I just watched the FabRats video and had to be impressed with how he did this while his left arm was in a cast. He made it look pretty easy, although he is on a lift and not on his back. I really hope this fixes the issues for him.

Good suggestion 64BAwagon. I hope you have better luck with the shape of your pan. Mine had distinct seams and wrinkles where it should have been flat. I had several of the Dorman and B&M kits on hand when I dropped my pan. I was going to pop one in but I convinced myself that the likely spots without internal interference were not flat enough on the pan. Rather than force the issue, I punted. I would typically put one in back in the TH400 days, but those had more obvious places to work. If I had my welding gear handy, I would have preferred to weld a bung fitting onto the pan in one of those corner flats. That way, it is not interfering internally, low enough to really drain the whole pan make it worth the trouble, and shouldn't ever be struck unless heaven forbid the whole trans pan is crushed.

The 2022 2500 HD Duramax trans pan is largely unobstructed and there isn't an exhaust under it. I'm in a 2022 High Country with about 45,000 miles of fairly light duty on the odometer. I have lost confidence in the folks who did this owner's manual so I decided I would do the maintenance rather than wait like the schedule shows. I am glad I did not wait. Based on this cycle and reading all the accounts of infant mortality and valve body back-orders, I will not wait long to do this again. The job is a pain because there is no drain plug for the pan, which means you have a pan full to the brim when you lower it. I used an assistant on a floor jack while doing this on the driveway. So, just for the folks who have never run the job, the link in the post above is going to show you the service manual procedures, including the need to do the torque stalls to get the unit to temp. I will just add a few things on what else to expect. When I first got started, on a cold truck, I pulled the lower plug to see if there was fluid above the standpipe level. I got close to 2 quarts doing this, so that step saves it from spilling over when you lower the pan. When the pan is lowered, because the volume of the flooded parts and filter stay up as the pan lowers, the fluid level in the pan lowers such that there is about a 1/2" gap to the top of the pan. If you keep the pan level, nothing spills. Some folks stop here and suction off some of that level. I just carefully lowered and removed the pan. You will need to lower and move slightly forward to avoid the obstructions to the rear. The recovered fluid totals out roughly 9 - 10 quarts. Skipping forward to putting fluid back... Filling the unit using the fill plug in the case means you are well above the pan seam. It will now require about 13 quarts to see it start to leak out of the fill-plug hole, but when you start the motor it will allow you to add more for a total of 15 quarts that most of the better filter kits are giving you. The extra volume ends up being the fluid exchange that flushes the remaining volume that was sitting in the rest of the places like the torque converter, cooling lines, etc.. When the 15 quarts have been added, with the plug placed temporarily in the case and the motor running, I brought the system to normal (about 140), I then ran just a few stalls and brough the temp to between 168 and 172F and pulled the pan plug to allow the fluid to drain to the stand pipe. This happens quick enough that the dashboard TFT stays at about 172F. The color of that fluid should look nice and red, not dirty or brown. If you get a chance to catch all that excess fluid in a clean container, you should see what looks like new fluid. If it is very dirty, looks like coffee, or full of chips, I would say you are in trouble. This procedure will spill back about 5.5 quarts, which means roughly 9.5 to 10 quarts have been retained out of the 15. Dear GM, not sure what the thought process was to omit a drain plug in the pan, or dipstick/fill tube so this could have been a civilized procedure, but tell that committee to think twice next time.

Hi Folks, it has been a little alarming to read the stories above, both from the technical view of the hardware reliability and design issues, and also from the dealership/GM and ethics view. It is one thing to release a transmission design and discover issues in the wild, but how they have been handled is another. Folks are paying ridiculously high prices, and most of us make payments monthly. Expecting to have one of these fixed in a timely way isn't being unfair to the dealers or GM, but expecting folks wait for weeks while making payments is alarming. I stumbled into this forum while researching to find out if the owner's manual maintenance schedule is an error, and started looking into that when I discovered how tangled the issues with transfer case fluid and axles were in the owner's manual. It is very disappointing to say the least. So I then wondered about the transmission.... I am coming up 47k miles and saw in some places that I am to change the transfer case fluid. Well enough there was no real problems there, but then it made me wonder where and when the axles and trans fluid would be by comparison. I won't go down the rabbit hole with why did GM skip the drain plugs on the axles for the moment. That is sad to see since the bosses in those cases where drain plugs should have been still exist. Can anyone say why the regular schedule versus severe schedule goes from no mention to service trans fluid/filter at all versus doing this at 45k mi for severe? How can there be no mention at all for the regular schedule for over 150k miles, yet only 45k mi for severe? Sounds like something is missing in the "normal" service schedule? What does GM really want for fluid/filter change interval on these 10 speed transmissions? Why omit the dipstick? Why is there such a huge difference from "normal" to "severe" and can we trust the owner's manual? Why omit a drain plug and fill capability to make testing fluid an option to see if a user is "normal" or "severe" and avoid failures?