Has anybody done this on the vehicle without removing the gear box? Just wondering if somebody has a trick to replace it without pulling the gear box.

 

You really cannot get a conventional puller on there with the gear box still mounted to the frame. I have always removed the bolts that hold the gear box on and moved it to where I can get a puller on it. This will require you to disconnect the steering shaft, but you should be able to leave the lines connected.