Revo motor mount and gear mesh

[jnev]

I installed the electronics from my buggy into my Revo and everything went great. I had a 18t pinion and 36t spur, and they meshed perfectly. But when I took the motor out to shorten the ESC wires, and I put the motor back in, the gears didn't reach. So after this, I installed a 38t spur. And the gears meshed perfectly again. Now today while testing it out, the Revo did great, but when I took the motor out for cleaning after the bash and put it back in, the gears once again didn't reach... This has never happed on any other car of mine before, but I just don't get how this is happening. The motor is pushed as far as possible to the spur, but still the mesh isn't close enough this way.

Please someone help. I found a great new bash spot (where I went today) and am hoping to go there again tomorrow.

Thanks.