I've seen a few threads about the problem I've had a few times these last months, so I just want to share my story/experience. I will not post a step-by-step guide on how to do this. I will not recommend this unless you are mechanically inclined or have someone who is with you to help.
I've now had my car for almost half a year. Ever since I bought it there have been a shudder in the transmission while going into 3rd, which I believe is the torque converter trying to lock-up, and a slight flare when the over drive (OD) band is applied. It was also slow at shifting gears and the shifts were rough. At first I had no idea what it was, but I found this link. When I finally got around to read through the entire site I knew what the cause of the shudder was and what would solve my problem. I got the new transmission fluid a few months back, but I didn't get around to putting it in until today. Because my GT is a 2003 model, my torque converter (TC) does not have a drain plug. I was hoping that I could completely drain the transmission fluid and put inn all new fluid (total of 12.8 quarts). I soon found out I have no drain plug on my TC, so dropping the pan was all I could do. Dropping the pan was no hard job, and was far less messy than I had expected. Got the pan out and cleaned it up with some lint-less paper.
Now, it is said you should change the transmission fluid every 20,000 miles or so, depending on how you drive (the handbook says to do it at least every 30,000 miles). When I dropped the pan I immediately saw the infamous "lollipop". This leads me to believe that the fluid has never been changed during the 132,000 miles it has driven. The old fluid was completely black, not a clear, red color like it is supposed to. Not good. After cleaning the pan and wiping off the stock OEM rubber gasket, I replaced the filter, put the oil pan back on and tightened it down to specs. At first I poured 3 quarts of Mercon V (from NAPA's own brand) and measured the dipstick just to get a pointer. I ended up putting in about 4.7 quarts. I cranked up the engine, pushed the brakes, and went from P to 1 and back, stopping for about 5 seconds on each gear just to cycle the oil. Took it for a little test drive and the transmission is sooooo smooth. The car honestly feels as smooth as my mother's 2011 Hyundai Elantra (6 speed, auto). I am planning on dropping the pan and maybe putting in a new filter in a few months or so, because there are still several quarts of the old oil in the TC (and there is no way I am paying someone 3-400 dollars for a flush).
On a last note, I said I filled about 4.7 quarts of new fluid into the transmission. Everywhere I have seen people will tell you to put 5-6 quarts in, but I highly recommend to start checking your levels for every half quart you add after the first 4 quarts. Also, at around 4 or 4.5 quarts you can crank up the engine and cycle through the gears just to blend the fluid before you add the rest. Be very careful not to overfill!! Overfilling the transmission with ATF will cause serious problems and damage your transmission.
I've now had my car for almost half a year. Ever since I bought it there have been a shudder in the transmission while going into 3rd, which I believe is the torque converter trying to lock-up, and a slight flare when the over drive (OD) band is applied. It was also slow at shifting gears and the shifts were rough. At first I had no idea what it was, but I found this link. When I finally got around to read through the entire site I knew what the cause of the shudder was and what would solve my problem. I got the new transmission fluid a few months back, but I didn't get around to putting it in until today. Because my GT is a 2003 model, my torque converter (TC) does not have a drain plug. I was hoping that I could completely drain the transmission fluid and put inn all new fluid (total of 12.8 quarts). I soon found out I have no drain plug on my TC, so dropping the pan was all I could do. Dropping the pan was no hard job, and was far less messy than I had expected. Got the pan out and cleaned it up with some lint-less paper.
Now, it is said you should change the transmission fluid every 20,000 miles or so, depending on how you drive (the handbook says to do it at least every 30,000 miles). When I dropped the pan I immediately saw the infamous "lollipop". This leads me to believe that the fluid has never been changed during the 132,000 miles it has driven. The old fluid was completely black, not a clear, red color like it is supposed to. Not good. After cleaning the pan and wiping off the stock OEM rubber gasket, I replaced the filter, put the oil pan back on and tightened it down to specs. At first I poured 3 quarts of Mercon V (from NAPA's own brand) and measured the dipstick just to get a pointer. I ended up putting in about 4.7 quarts. I cranked up the engine, pushed the brakes, and went from P to 1 and back, stopping for about 5 seconds on each gear just to cycle the oil. Took it for a little test drive and the transmission is sooooo smooth. The car honestly feels as smooth as my mother's 2011 Hyundai Elantra (6 speed, auto). I am planning on dropping the pan and maybe putting in a new filter in a few months or so, because there are still several quarts of the old oil in the TC (and there is no way I am paying someone 3-400 dollars for a flush).
On a last note, I said I filled about 4.7 quarts of new fluid into the transmission. Everywhere I have seen people will tell you to put 5-6 quarts in, but I highly recommend to start checking your levels for every half quart you add after the first 4 quarts. Also, at around 4 or 4.5 quarts you can crank up the engine and cycle through the gears just to blend the fluid before you add the rest. Be very careful not to overfill!! Overfilling the transmission with ATF will cause serious problems and damage your transmission.