Help If Ur Akle is loose and it just falls out.
 

what I did was i simply broke a piece off of a paper clip to be a little smaller axle. then I put It in the axle so it is diagnol then walla ur akle won.t fall out/ ur gears won't sound really weird and grind when u stop

Some Pics
 

The Paper clip Is like a staple I bent it with pliers

Here this might help...
 

This is the clip in and putting in I used pliers cuz my fingers r too big and u can't see the clip but u can use ur fingers

U can tape it
 

U can tape it with durable tape like duct or electrical just don't use scotch

This Is How I taped it
 

this is the diagram green is tape purple is the staple this little thing is pretty nifty huh?

jbweld it dude.

The JB Weld technique is a good, permanent fix and as I understand it, makes the rear axel much smoother. It can look untidy, but if you take time and sand, paint flat black and such, you can get a really strong, smooth fix. Only drawback is you can't change axels out anymore. Another solution is to cut a sliver of plastic on the loose side to close up the hole and back fill the gap created on the other side with epoxy. This works well, is barely noticable, and allows for changing gear sets. If you don't plan on changing gears anyways, the JB Weld method is the way to go.

Here's how you fix the loose rear axel with the slice and glue technique. First. slice a small wedge next to the axel hole that produces a small sliver of plastic that you can bend inward to close the hole slightly.

Next, back fill the gap you made with epoxy to hold the little sliver in it's new place.

Now, you have a secure axel that spins freely and can be interchanged with other gear sets. Simple as that.