Mine was on the outside. One was missing from the unit when I picked it up and I found out after driving many hours. If this is occurring, you'll know because one side moves quite a bit while the other doesn't. If one side moves and shuts off automatically, it's a different issue.
If the motor has hopped out of its mount, you should be able to line the slide up pretty well, then push the motor back into it's spot. I was able to lift the motor up to see the 'notch' that it is supposed to fit in. Then I could push it back down. Since the screw was never in the motor, I couldn't just add one (I couldn't see where it was supposed to go and I didn't have the tools with me). I made little shims to stick above the motors so they couldn't bounce out of their mounts until I could get the screw put in.
Tim, Tara and Canyon - 'TnT' (& C now...)
2015 Thor Outlaw 37LS w/FJ Cruiser Toad
Columbia 400, 1967 Corvette, KTM 350 EXC-f, TTR 125 LE, XR50 for toys