904 trans with electric TCC lock up feature.
Not sure if this will help in your search, but from what I've found the lockup override (tow/haul switch) didn't seem to appear until the late 80s/early 90s when they changed the designation from A999 to 32RH, and they began appearing in light duty trucks like Dakotas, V6/318 half-tons, and vans.
The issue with the late version is that there were reinforcing ribs added to the tailhousing, which, depending on your plans for the transmission, can interfere with the crossmember- I had to nearly completely remove (grind off) the ribs on top in order to fit one into my '66 (it was a '91 trans), later A bodies may have more room and not have this issue, I have not tried one yet in a '67 and up. The A999s don't have this issue, but they don't have the tow/haul override, either, from what I have seen.
Not sure if this will help in your search, but from what I've found the lockup override (tow/haul switch) didn't seem to appear until the late 80s/early 90s when they changed the designation from A999 to 32RH, and they began appearing in light duty trucks like Dakotas, V6/318 half-tons, and vans.
The issue with the late version is that there were reinforcing ribs added to the tailhousing, which, depending on your plans for the transmission, can interfere with the crossmember- I had to nearly completely remove (grind off) the ribs on top in order to fit one into my '66 (it was a '91 trans), later A bodies may have more room and not have this issue, I have not tried one yet in a '67 and up. The A999s don't have this issue, but they don't have the tow/haul override, either, from what I have seen.
