I've got a 55 gmc 550 tandem axle,, with an inter axle differential lock on it (vacuum).. It looks like a transfer case ahead of the first axle,, with the rear drive shaft, for the rear axle, that comes "over" the first axle, to hook in on the "transfer case".. Is this common for this era? I've not seen this before on newer big trucks. Are there many problems with this kind? It looks like a heck of an angle on the shaft for the U joints. I know it's for only a second one would engage it (to get out of being stuck), but it looks strange to me. It, I was told, IS original.
