What was the purpose of the “enclosed drive line”? Was there a reason for it, or was that just the way it was done? Someone told me that was designed for the terrain of fields and such “out on the farm”, so as to not get things wrapped up in the shaft…?
The enclosed driveline, or torque tube, is really a very effective design.
Its advantages are positive location of the rear end, with no Panhard rods, traction bars, etc needed for stability. Only one U-joint is needed, and it runs in a constant lube shared with the transmission. It was used in many passenger cars so I doubt the “out on the farm” angle. The newest hi-zoot Jags and Aston Martins use a torque tube driveline, so it can’t be all that bad.
The main negative on an enclosed driveline, though, is that there are very limited ratios available for the rear end. Also, U-joints are expensive and more complicated to change – and the seal which retains the lube in the tube, when worn, can cause all the tranny lube to drain back into the rear housing, and eventually into the brake drums.
When everything’s in good shape, the torque tube is fine for its intended purpose. When it wears out, or we change that purpose, it’s a major pain in the rear!