Thank you Brad, the first link you provide, '1948 Servicing Truck Cabs', is what I had seen but not remembered the source. I got a couple of parts latches from Jerry Rivers so maybe between them and the one on my truck I can figure a way to make one of them work. I'll start by re-adjusting the relay for the lock. It might be that I adjusted it too far and somehow that affected the function of the outside handle. I'm still hoping someone has fixed the same problem I'm experiencing and knows what I need to do!