Just an update on mine - the amazon seal I linked to earlier in this thread was incorrect (too large). Reassembled it with just the larger Toyota o-ring installed and now the flashing CDL won’t go off, despite a number of attempted fixes and much research. I may have reassembled it incorrectly...
Gonna try this one - wish me luck.
https://www.amazon.com/National-710254-Oil-Seal/dp/B000C5J16C/ref=sr_1_1?ie=UTF8&qid=1541454599&sr=8-1&keywords=transfer+case+seal+gx470