Actually the '70 510 AT Wagon was my second 510. I traded in a '68 coupe for the wagon. At the time I was stationed on the east coast at Dover AFB Del and was temporarily assigned to the Edwards AFB CA. After getting there, I rented a home right outside the base and had a 26 mile commute to work. Between the long daily commute, weekends in Las Vegas and the cross country relocation, I put the 11,000+ miles on in only a few months. I was on my way back to Dover transiting Arizona when the transmission ate itself. Since the JATCO transmission had only been sold in the US for a few months, Datsun had no spare parts.
The Dallas Datsun Sales Manager was all kinds of angry when he had to take his only AT equipped Wagon off the floor to cannibalize parts.
Datsun dealerships of the time were somewhat spotty, especially out of the major markets. The dealership in Winslow AZ where I had my problems turned out to be the John Deere Farm Implements dealer. The head (read only) mechanic was the owner's son. He confessed that he had never seen any car with an automatic transmission. He was kind enough to write a letter verifying that the failure had occurred while the car was in warranty.