Good job!
Any restoration job that comes through my shop gets any gearboxes that will come apart taken apart, the innards 'hot tanked' in my ultrasonic cleaner, and reassembled with teflon gel lube. Amazing how the lube Multiproducts used in these turns to varnish over time.
What held the case together? Screws? Can't see from your pic, and I've never done a JD.