I used a lawnmower/motorcycle battery, worked fine and is easier to carry.
Beware of this job! I did this last night and it took me 6 hours. It's about 3 times as hard as my list I made above makes it sound. I took some pics of all the wires that are gonna be hanging down while you do this, but I can't upload them yet 'cause my camera software is wacked. Anyways you are going to have to remove a TON of connectors when you take the CPU out (maybe you've done this before though).
And make sure that no pieces of your old antenna gear borke off and are still in the motor. If the end of your old antenna gear is blunt like a piece broke off, and you don't see the piece anywhere, first run the motor backwards to see if it gets pushed out of the motor. If that doesn't work, TAKE THE MOTOR APART and MAKE SURE there are no rougue bits inside!!! I did not do this, and it turned out that there was a piece inside of mine, and I have to do the entire job ALL OVER AGAIN! It totally sucks, but hopefully the second time will go faster.
Taking the CPU out is hard to figure out if you've never done it. There is a little tab at the top of it, in the center. You have to pry up on this tab, and pull out on the CPU box at the same time to get it out. Very difficult. I am lucky I have small hands and can do this stuff. There are many things I've done where I thought it would be impossible to do if I had bigger hands.