tldr: i think i over filled it by many many quarts, maybe even a gallon or two too much, thanks to my not putting the dipstick filler tube down into the whole all the way on the transmission.
what did i destroy and can this mess be salvaged?
long boring version: background, i bought this 2004 transmission used from a junk yard becuase i destroyed my original a few months ago by not having the torque converter fully seated. this stinks as this job started as just a cracked flex plate.
anyways change out the transmission and everything seemed fine for about 2 months and or 1000 miles until all at once it started acting weird, loss of power and then it wouldnt even drive at all, this first episode of acting up started with weird noise, loss of power then went limp in about 3 minutes, after about a 15 minute drive.
parked it, then towed it home to discover its working again, but after driving for about 20 mins it starts making noise and goes limp again, let it sit 10 minutes or so then its runs fine again.
i assumed it was dirty trans fluid plugging the filter, so i changed the filter and the fluid in the pan, early in the process of changing the filter i noticed it was leaking bad all around the pan gasket. i also noticed the dipstick tube was not fully seated, in fact i would say it was raised up about 1.5 inches from where it should have been, which means i over filled the transmission by a lot.
so, tonight again i started it, drove it around and it felt great shifting and the torque converter even locked as it should. but then i noticed my engine rpm started to vary a tiny bit on the highway, and this variance seemed to be in the rpm range of torque converter lockout to not being locked. then the torque converter just stopped trying and so now im cursing down the highway at 60mph with an rpm of about 2k, instead of the normal 1.6k or what ever it should be.
i give it some gas to down shift and accelerate and it tried but it seemed to start slipping, pulled off the road and as i came to a stop i noticed i now dont even have drive.
i let it sit for about 5 minutes, start it back up and again its now driving like it should. but while driving down the road it went limp again this time it only took about 5 minutes to go limp. luckily i was able to pull into my drive and let it sit.
after sitting about an hour, i started it and it felt great again and was able to drive around the properly. i pulled up to a tractor on the farm and hopped out but let the trailblazer keep running for about 15 minutes, and after a while i could hear it making noises. it almost sounded like a rattling noise, almost like heat shield rattle, but i feel like it was the transmission as all my heat shield mounting points have recently been reinforced. went to drive it and i didnt have drive again.
let it sit for another hour, started it, and i could hear transmission noise for about 1/2 second, then it cleared up as if fluid got to where it was needed before but couldnt get there for some reason. and it was drivable again and great again.
i checked the fluid cold tonight after letting it sit for two hours and it was just below the upper fill lines, the dip stick said it should be between the two lines when warm, so i feel it has the proper fluid level in it now.
where do i go from here? did i destroy this transmission? should i try to fluid all the fluid, or change the filter again?