My best guess is someone put a 1948 to 1953 3/4 ton 4 speed tranny in your truck. The reason I say that is because the rear yoke is shorter, which is used in the 3/4 ton partial torque tube/open driveline. 2nd photo
The 1st attached photo is the type of u-joint you need. Note the longer rear yoke. The front yoke is hard to find.
