I had to look long and hard on how to properly do this, so I figured I'd take some pics while I was doing it so that you guys can do it too.
Host vehicle: 2006 Cobalt LS Coupe 2.2L 5 Speed Manual
Time: 30min-1 hour
What you will need:
3/8" ratchet, couple extensions (one really long one)
8MM hex socket and 8MM stubby hex key(I'll explain later)
5+ quart drain pan
long, skinny funnel
towels for messes
Jack and jack stand(s)
2 quarts of Dexron III ATF fluid H-SPEC(Be sure to check your owner's manual first, yours maybe be different than mine)
And get 2 quarts of the GOOD stuff. This gets involved and it's only 2 quarts! I'm using Royal Purple ATF. $13 a quart, but it's still chump change for the all important transmission.
OK, first put on your e-brake, put down wheel chocks on the rear tires, jack up and properly place jackstands in the front. Try to keep the driver and passenger sides as level as possible. After that's done, remove the driver side wheel.
Now, this is the easiest way of doing it that I found. Locate the upper and lower plugs.
The lower plug is going to give you some trouble. Remember the stubby 8MM hex key? A regular key is simply too big to fit in between the frame piece and the plug, so grab a 8MM key you don't care about cutting and cut it to a shorter length so that you can loosen the plug without interferance.
Place your drain pan under the plug location, use the 8MM socket and a long extension to remove the upper plug.
Now, use your stubby 8MM key and remove the lower plug. I couldn't grab it once loosened, so I let it fall into the pan and fished it out later. Use caution if you are using one of those enclosed drain pans or you will really be fishing the plug out of that one.
Now, while the fluid is draining, locate the top plug. It's right inbetween the engine and the battery terminal box. It should be the only plug on top of the transmission. Removeal of the plastic ECOTEC engine cover is required.
Once you've located it, clean off all the debris from around that plug. Last thing you need is road grime and dirt to fall into your transmission. Wipe it clean, use a blow gun to blow away and loose dirt, get it as clean around that plug as possible.
This is where the really long extension comes in. Guide the 8MM extension inbetween the hose and wire jungle down to the top plug, loosen it and remove it.
By this time, all of your fluid should be drained out. Fish out your lower plug, wipe it off, reinstall it to the lower(drain) hole and torque it to 28ft lb's. Don't wipe off the "ATF river" just yet, because now it's time to add the new ATF.
Grab your long funnel, or you can use this style that my brother bought for his hard to reach spot on his car, carefully maneuver it between the wire and hose jungle until you are securely set in the top hole.
With your drainpan still in place, add 1.8 quarts of ATF. I just dumped the full 2 in because I don't want .2 of a quart sitting around the garage never to be used again.
Anyway, when it gets full, the ATF will start to flow out of the upper hole. When it does, let it drain out until the fluid is level with the bottom threads of the upper hole.
Once it's level with the bottom of the threads, you have put in the correct amount of ATF. Reinstall the upper and top plugs and torque them both to 28 ft lbs. At this time, reinstall the ECOTEC engine cover. Now you can wipe off the ATF river and properly dispose of the old ATF
IF FOR SOME REASON YOU HAD METAL SHAVINGS OR ANY FOREIGN MATERIAL DRAIN OUT WITH THE FLUID, GET IT LOOKED AT RIGHT AWAY!
Reinstall the wheel, torque the lug nuts to 100 ft lbs and you are done!
If I overlooked anything or missed something, let me know.