Easy process. I did it three years ago when the original tank developed holes. I did it flat on my back on the grass. As I recall you just have to undo some straps, maybe a skid plate, pull the fill tube, and disconnect some smaller things as you drop the tank. There will be some small things you must transfer from the old to the new tank. It's all pretty obvious once you start. I'll add a picture of the tank if I can.

I didn't have to worry about draining the tank, as you can see in the picture. The hole is by the far strap.

[img][image]http://i82.photobucket.com/albums/j252/4breezes/1984%20Montero/DSCF6922.jpg[/img][/image]