i changed fluid today after doing some research, most of the fluid changes that i saw was draining the fluid then removing the full plug. i decided to remove the full plug first and 1.5 liters of fluid cam out before i removed the drain plug. a total of almost exactly 5 quarts was removed. all of the research i did showed between 3-4 quarts by removing the drain plug first. what's up with that, was my tranny over full from the factory? i put the exact amount that cam out back in. the car ran great before and after the change. i'm just wondering if people are under filling there trans by filling till fluid comes out of the full hole.
You must not remove the "check" level side bolt unless the engine is running.
The procedure is on several YouTube videos similar to the Sonic using the same class of transmission as on the Chevy Cruze.
You drain, measure closely each quart and partial quart (ounces) you drain out. Then fill with the same amount. Start the car up, parking brake on, foot on brake, cycle through the gears several times and pause in each one for 3 seconds. Repeat at least 3 times.
Let engine idle for 5 or 10 minutes - - - ideally till transmission temp is +195F.
Then, car on flat and level surface with engine still running and in Park. . . . loosen the side level checking bolt. Fluid should just barely trickle out. If not, add some slowly a little at a time. Do not over fill.
If the transmission is not at +195F, best to under fill an ounce or two.