I started to take apart my D44 also and noticed what falcon is noticing. I've serviced three other cars I have with similar axle retention. A 69 Pontiac, 77 Celica, and a 92 Toyota Pickup. Like the D44 they all use a retainer plate to keep the axle in.
However all the other three use unit bearings where the retainer plate acts against the OUTER race of the bearing. The outer race of the bearing is then locked into place and the axle is kept in place by the press fit into the inner race of the bearing and the pressed-on-retainer aids retention.
The D44 differs in that the bearing is a conical bearing which can handle much higher side forces in one axial direction and none in the other. So to keep the axle from popping out, the retainer plate must act against the seal which then acts against the inner race of the conical bearing. If the side forces exceed that which the seal can handle and as such the seal compresses, then there will be play allowing the bearing to come apart slightly and pop back in as the vehicle turns left to right visa versa. If this is possible, I don't know, but I was much surprised to see the the D44 designed this way.
I've heard that there are unit bearings that fit in the D44 but I'm not sure if this is better that the conical bearing. My intuition tells me its better but what does everyone else think?