That must be the tranny I had in a short Dodge 1/2-ton, a '78 I think, with a 318. I liked it, because it felt exactly like a 3-speed, but with a whole, long top gear above the 3rd. If you put it in at, say, 55 mph the engine speed would drop to a fast idle, and she made phenomenal fuel economy.
My friend once put 50 miles on it following our bikes on a canyon road before he found the top gear.
