Well I just got it!! Since he said pressure, I took the handle end of a ball joint separator between the axles and pushed on the forked end against my shoulder using the frame as leverage and it moved so I rolled the spider gears in without the thrush washers first. Then I used the ball joint separator and shoulder method to apply outward pressure on the axles and it created a gap between the carrier and the spider gears enough for an oil coated thrush washer to slide right in! Did both and now the carrier pin slides in with no problem. So obviously the thrush washers installed put enough pressure on the side gears for the carrier pin to go in. Interesting. I love learning new things.