Im going to change my trans fluid this week, anyone got some good tips and steps to do this job?

Another question, is the exact number and kind of transmission in a 2003 Pontiac Grand Prix GT 3800 Series II

Large drop pan to catch the fluid, tape down some plastic garbage bags or something so garage floor cleanup isnt to bad, and have plenty of rags.

Make sure you get that old seal out, and the new one goes in correctly, or else you will pump air through your tranny... Not good

Dont forget to put the magnet back inside the pan.

Chock the rear wheels if you use jackstands to lift the front

Dont over fill

Loosten all the bolts on the pan. Then remove the ones near the corner closer to the back passenger side more so that it will allow the fluid to drain at one corner instead of the whole pan. The seal on the trans filter is not actually necessary to change as long as the filter fits tight up into it. Make sure to put the magnet back ( I forgot and it costs me another $25 to drop it again just to put the magnet back.). Check your gasket on the pan. I know they are reusable but mine was hard as plastic so I deemed it better to replace than possibly not have a good seal. Your filter should come with a new rubber one(at least mine did). Make sure to use a torque wrench on the bolts when putting the pan back. There's a good write-up on the maintenance forum near the top of the grand prix forums.

Another question, is the exact number and kind of transmission in a 2003 Pontiac Grand Prix GT 3800 Series II

4T65E. GM RPO Code M15.

I bought a oil pump from Warshawski's. All I have to do is to pull the dipstick and put the plastic house down the dipstick tube. Turn the pump on, and pump out the trans fluid. Jack up the car and pull the trans pan and replace the filter. This is real easy and much less mess.