The torque tube arrangement also employs only one u-joint which is in the rear of the transmission. At the axle end the spring holders have a pivot pin in them so the axle can rotate backward and forward. If you ever take out the transmission and put a jack under the torque tube you can see the wheels moving in the wheel well. I also believe that is why the wheels are not centered in the wells. In the torque tube there are bushings and a seal, the latter keeps transmission oil from going down the tube to the differential. If that seal goes you will never keep oil in the trans as it will overflow into the diff and either blow out the vent or axle seals. Been there done that.
