Drive shaft differences, Why?

[Ridgerunner]

On the Deuce, why is there two different style u-joints shafts on the truck? The front shaft and far rear shaft run just a standard u-joint, where as the middle shaft (from t-case to middle axle) uses the bolt on caps. How come it doesn't use a standard u-joint on this shaft?

I'm going to bob my Deuce soon and I'm going to set the axle back just a bit from the stock location, so I have to get a longer drive shaft. So which drive shaft would be the best one to lengthen?

 

[Jones]

Not sure either. One possibility is that with close tolerances they may have figured that a "Mechanics" type u-joint would be easier and faster to change out than one you had to thread the ends of the crosses into then bring in the caps with needles and hope that nothing dropped out while assembling.
Of course that logic fails when you have a Mechanics type on one end and a Spicer type on the other of the same drive shaft.

 

[Ridgerunner]

This is a bad question, or no one knows the reason

 

[Recovry4x4]

I would think because the joints are bigger.

 

[tie6044]

I've always just assumed it was just to use a bigger joint. It seems that 99% of the deuces have that bolt in cap type on the rear shaft but I have come across 2 that had a standard looking u-joint but it was even bigger than the bolt in cap style, anyone know what they came off of? The only one that I saw still on the truck was from a 109 but nothing special about it.