The CJ-4 versions are not the same oil anymore. Previous CI-4 and CI-4+ versions were though. TDT and D1 ESP meet different specs and have different properties.
My thread over on TDI Club has more info:
They are not exactly the same. They are reasonably close enough for our day-to-day comparisons, performance wise.
The real significant differences are in the marketing. Delvac 1 is seen at OTR truck stops and service joints. TDT is seen at your local auto-parts and WallyWorld places.
They are different, but your vehicle (whatever it might be) is likely not going to be able to distinguish the difference.