Goob,The "Hi/Lo" shaft,below the "Pancake",is in an almost vertical position. when the "pancake"/shaft loses vacuum,(holding it up),it may "drop" out of gear,which could result in catastrophe! Another thing that you NEVER want to trust is a "Hydro-lock" brake switch! Check-out Jeff Bradshaw's'55 G.M.C. 350 dump truck,after the Hydro-lock" bled-off! Same thing could happen,if you leave your 2-speed on the "Hi"-side! These things are designed to be shifted under vacuum.And,yes,if you accidentally switch the selector with the engine off,you may have to manually engage the shaft,("Lo"-side). I tried to engage it,(like a dummy),on the "Hi"-side,but by the time I got the bolts tightened back up,the shaft would drop. The shaft as a notch forged in it,at the same angle as the tang,on the selector switch,in the rear-end. Make sure you "Permatex" the housing,or it will leak. If you're on the "Hi"-side,with the button "Down",switch your hoses at the "pancake".Hope this helps.
