SHS Motor Problem
 

I bought my SHS High Torque Motor about a year ago, and now every time I remove the motor from my grip, it seems like the pinion gear never stays on the shaft. It's gotten to the point where the pinion can easily slide on and off, and I did nothing to the pinion or shaft! Is this a common problem and is there a simple fix or do I have to buy a brand new Motor? Thanks in advance!

There is a grub screw that keeps the pinion on the shaft.

It seems like the grub screw is still there, but has loosened itself. Any idea what type of screw is needed to tighten it?

I think its a 1.3mm Hex

Also known as a 0.050" one. That's what I use (my metric set doesn't go below 1.5mm)

When you tighten the screw pull it almost all the way out or all the way out coat it in loctite and then put it back in, if you ever need to change the pinion in the future just heat it with a lighter or a torch.