now place the new gear in the motor side of the housing mount the motor ans set the pinion depth to the gear
now press the driven gear of the output shaft and revese it on the shaft 1/8 of the spline should be showing when done and make sure the front bushing is in place then reassemble the gearbox and your done

http://www.youtube.com/watch?v=4POZPbaTokM the running gearbox noisy no lube in it yet