It's possible, but VEEEERRRRY easy to crack the glass. Ask me how I knowk i just recently installed 62 mirrors on my 60 and both the glass mirrors were broke. so i ordered them and they just glued to the back plates which just snapped onto the pivots from what i can remember. So you should be able to pop the mirror and back plate off by just prying and have access to the motors. And thats all if i remember correctly.
I had actually tried that in the past, but the glass still broke. Once I have replacement glass in hand I'll try it again, but I'm not expecting to avoid breaking it.STOP!!! You can pop the pad that the glass is on off the assembly itself. There are 4 balls in sockets that connect the pad to the motor. It's easy to crack the glass, but that can be replaced. The biggest thing is not breaking the pad. I broke the sockets on my driver side mirror, and haven't had a mirror in a long time... Where do I get a new pad??? I'll post pics tomorrow of my mirror