In the video, you will witness the installation of a pinion gear, without the help of anyone else. To install both pinion gears, use this method with both pinion gears simultaneously. Place pinion gears exactly opposite each other through window of carrier, slightly pushed into one rotational direction so that they hang on the side gears' teeth. Confirm they are exactly opposite each other by viewing through the hole at center of the pinion gear. You should be able to see across to the other pinion gear and the holes must line up and appear to be in a straight line from each other. Finally, walk the gears further into the carrier cautiously by turning one side gear at a time as seen on video.
In the video you will see a differential housing on the axle, dry and uncovered. Ring gear, side gears, and axleshafts previously installed and held in place. A breaker bar wedged between axleshaft tips, a pinion shaft slightly inserted into place and sticking out far enough to keep carrier from rotating, but not inserted far enough to block pinion gear from being installed. Pinion thrust washers may be installed after the pinion gears are walked into position and before the pinion shaft is fully inserted. Use extension or similar tool to insert into shaft hole to help line up each of the washers once they are carefully tapped into place between pinion gear and carrier. Rub gear oil on any part that refuses to slide for you. Avoid using too much oil as job may get messy and could attract contaminants.
One 1/2" Drive Breaker Bar to slide in center between axleshafts.
One 1/2" Drive Extension (about 8" in length) to help turn the breaker bar so that the width of the breaker bar helps spread the axleshaft tips apart, thus leaving breaker bar wedged in position.
One Zip Tie to hold pinion shaft in place.
One steel pipe for help turning wheel studs or bolts to get the side gears to rotate one at a time, thus walking pinion gears into place.