Trike Rear Axle Removal Problem

[Prof. Wheeler]

Hi Everyone. I usually can figure things out but this one has me stumped. I am refurbishing a Hedstrom Trike from the 1970's or 80's and I can't for the life of me get the rear axle/differential out of the frame. I have taken a lot of pictures and I hope someone on here has an idea of how to move forward. The bike has a 3-speed internal shift hub sistered to a chain drive differential of some sort. The rear axle is definitely two separate pieces but neither will come out of the frame. I managed to get the right side wheel off but the left remains a problem. It doesn't seem to thread off or slide off. The thing must come apart somehow but I just can't seem to figure it out. Anyone got any suggestions?
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