'53 3100 did not have a yoke on the rear end. Below is the drawing from the '53 GMC manual for 100 series. Same as Chevy 3100.
If you are speaking of the U-joint (not yoke) at the front of the torque tube it is held to the transmission output shaft by a 3/8-24 bolt and a thick washer. If your rear end actually has a yoke that takes U-bolts or straps to retain the needle bearing cups to the yoke then the rear has been changed to an open driveshaft unit. If the latter your local parts store should have what you need.
Is it possible to replace the center section to one without the torque tube and use a regular driveshalf? I am replacing the motor and trans with a 5.3 and 4l60e, replacing the whole rear end is not in the budget at the moment, what can be done? Plus I want to keep the 6 lug original wheels I just replaced and painted, help?
Short answer---NO. you do not show where you are located but if near north Texas we have several 55-59 pull outs in the rear end scrap pile that are waiting for scrap prices to go up. The factory 3.90 ratio is ideal for an overdrive transmission. 99% of our street rod builds have disc brakes and five bolt wheel patterns so factory stuff is not saved where it would take up valuable shop space.