I fixed my power antenna yesterday. Super easy and if anyone has a broken mast this will totally help.
Heres the mast I ordered
AntennaMastsRus A084-515821 2001-2006 Mitsubishi Montero Power Antenna Mast
https://www.amazon.com/dp/B00JS9QHKG/ref=cm_sw_r_awd_R3Yxvb0TW523S
$40 on amazon.
Tools needed
I had to find a long piece on metal to put inside the broken mast so it wouldn't collapse from the force of the vise grips.
Use a little penetrating oil around the base of the old mast because more than likely it will be stuck on there.
Old mast out
New mast in
It will take 2 people for this, 1 to turn the acc on and off, and 1 to feed the cable into the power antenna motor.
Edit: in order to get the new antenna all the way seated in the post I had to use a rubber mallet to tap it all the way in.
End result
Montero power antenna:
http://youtu.be/ICLg-HwbqYc