What exactly is the purpose of the rubber bands that come with the drill motors? :]
I believe it’s to hold them in either high or low gear.
A zip tie will work well too, however.
Good luck!
Matt
I believe it is to hold in the shifter clips.
I have no clue!!!
The easiest way to lock the trans into low is to pop of the black part that goes over the motor rotate it 90 degrees then put it back on 
P.S. Found that out last year by accident at the buckeye regional. LOOOOOOOOOONG STORY 
If the clip does pop out, can i just push it back in? This happened to us and we think the shifter may be not engaging when it is supposed to be. Is that related?
Your in bad shape when the clip pops out. This is what the rubber band is for and I urge everyone to use their. We already lost a transmission because the zip ties we were using loosened up and the pin popped out and the place shifter broke. Use the rubber band to hold the clips in place and use zip ties to keep the shifter in place. It the clips do pop out you will have to look at the motor diagrams, I think their is on in the white paper, because I don’t think it works quite right if you just pop the pin in.
<sarcasm> These rubber bands serve a far more important purpose. They are to be used instead of screws, bolts, super glue, duct tape, or whatever you wanted to mount your motors with. This can be achieved by creating a simple figure 8 with the band, wrapping one side around the motor, and the other around some kind of shaft </sarcasm>
Now while this may seem like a good idea, remember that rubber bands can snap really easily, so it’s not advisable hehe.