If you have the rear end off the ground, and jack stands under the rear frame (raising/holding the frame), you can disconnect the torque-tube/u-joint and slide the rear yoke rearwards.
Then, raise the torque-tube out of the way (I use a 2x4 between the frame side-rails to raise/hold the torque-tube completely/safely upwards).
Then, you can remove/install any original 3-sp/4-sp transmission, and easily lower the torque tube (with a jack) and install the u-joint, etc.
