Thanks for clearing that up, seems to me I actually were doing it right... but it wasn't the problem in my skills, it was the problem in the metalbody. The hole in the crane was too small but I solved the problem and I now have my gearbox in, yuippee!
Unfortunately now I have another problem with the metalbody and would ask for your opinions on what to do.
The wireing wont fit back into the cranestock because the metalbody is missing this hole which the wires are suposed to go through.
So, should I drill a hole to it or what? I'm open for suggestions before I'll go medieval on it.