Manual transmission gear oil change HELP!!!!!!!!!!!!!!

Yes I have searched I even searched the old aveo forum and the Daewoo forum. My third gear grinds most of the time above 3k shifting into third gear. I know my clutch is fine and the clutch master cylinder is fine. I have some very expensive mobil synthetic gear oil sitting here waiting to go into my tranny but I cant figure out where the drain plug is. I have searched and searched and searched under my car and on the internet I know where the fill plug might possibly be viewtopic.php?f=6&t=883 is that correct? I know some of you have changed there gear oil so I will be pissed if noone replies. Thankyou very much
Travis

You have to remove the 8 or 10 screws that hold the bottom plate of the tranny out to remove the oil. Remove the bottom plate and clean it, then put it back together and fill it up via the fill plug at the top.

Will I need to replace the gasket for this cover or should it be fine or do i need one? So just removing the cover will have the tranny oil dump out or is there a plug under the cover? How many quarts of gear box oil should I add?

I just wanted to see if any of you have done this job. So I want to remove the pan at the bottom to drain...correct? Do I need to replace the gasket...or is the same one reusable? Is it a rubber gasket, or something in a tube that forms a gasket? When I add the new oil...do I just add what is given in the owners manual? When I remove that plastic plug to add, do I need to loosen the bolt below also? Any help you could provide would be appreciated. Many Thanks!