This press work won't be for a five minute job; this will be a four hour job so Robbie will need a press for the day. He'll be removing the pinion bearing few times to get the correct gear pattern and that takes time. I'm sure someone else has a press in the club. Also, he'll need a bearing separator as well.
for set up purposes, we (my mechanic buddy and i) wallowed out the old bearings so they slipped on and off easier. then just press on the new ones when it's ready for final assembly. i even saw this on an episode of Trucks or Extreme 4x4.