a strange one...

hi guys, i have a very strange problem with my castle neu 2200kv motor. after running for a little while the motor shaft comes out the back of the motor and causes the pinion to no longer be in line with the spur anymore. i have no idea why the hell it is doing it as it is not over or under geared (12/62 in my x1-crt with 5s 6000mah enerland lipo) it has never been mistreated and i have checked for binding or whatever else could cause this but i have come up with nothing and i am stumped....
any ideas what i should do with it, fourtunaly i have another Neu on the way for my 8ight so at least i will have a car to play with for the moment

thanks richard