Use only Honda ATF Z1 and nothing else. Use any other fluid and you will experience shifting problems.
Same place you check the fluid level.
3
The 2003 Honda Accord has a 5-speed manual.
Honda recommends changing it at 100,000 miles. I personally recommend you change it every 75,000 miles. The 2003 Honda Accord had problems with the transmission so I would recommend this as a preventative measure.
You add fluid the same place you check the fluid level.
In the transmission?
no
Use ONLY genuine Honda ATF-Z1 A/T fluid and nothing else. Do not listen to anyone who tells you that you can use any other fluid that claims to be compatible. DexronIII can be used in an emergency but must be removed ASAP. Honda fluid is not cheap but way cheaper than a new transmission. The 2003-04 had a recall on the transmission for poor lubrication of one of the gears. Make sure the recall has been performed on your Honda. Change the fluid every 50,000 miles religiously. The 2003-04 Accord transmission is the weak link in these Hondas. I know as mine went out at 70,000 on my 2004 Accord. Honda replaced it as free of charge as I had a certified used Honda extended warranty of 8 years 80,000 miles. They have replaced many of these, so be forewarned and take care of yours and hopefully it will last.
You don't. It has a lifetime internal filter in the transmission.
It can fail suddenly. There is a recall on all 2003-2004 Honda Accord transmissions as there was a problem with lubrication.
http://www.v6performance.net/forums/7g-honda-accord-technical-discussion/214348-6-speed-manual-transmission-fluid-change.html
the engine oil and trans oil is all in one!