I have many time done what chadkiser describes (with an SM420 4-speed).
Jack stands placed under the axle housings and a floor jack under the torque-tube to lift the tube up to the floor.
Then put a 2x4 inside the frame-rails so that the torque-tube is held out of the way. Then, the the floor jack can be moved out of the way and be used under the transmission.
Use two transmission bolt "guide pins" as described above. I had to use one upper pin and one lower pin. Two upper guide-pins would not work on my SM420 and clutch housing. So, one upper (longer) pin was screwed into the clutch housing and one lower (shorter) pin was screwed in on the diagonal into the transmission. The lower pin has to short enough to be unscrewed from inside the lower clutch housing.
