'49,
Heck, I can't drive it on the highway NOW...LOL...
Any speed above 40 MPH, the vibration will shake the truck apart.
Dad had the original yoke neck machined and a new bushing installed by a local machinist, but when he put it back together, he didn't pre-lube the bushing, and it wiped-out again on its first trip...
This appears to be a '54-only set-up, as the later trannies have a slip-joint on the rear ?