Power steering gearbox issue

[bolivier]

I'm working on a '68 c10 with power steering. Got a remanufactured box. Brought it home, and the rag joint couple won't fit the shaft. The new box has a bigger diameter than the one that came out of the truck. I'm beginning to think the one in the truck is not the original. The research I've done says I have the correct replacement. A new couple is like $40 at oreillys. I'm thinking this might be a car box. The one that came out of the truck has 4L stamped on the side. The new replacement had only the number 4. This sound familiar to anyone?
First pic is reman. 2nd was in the truck.