The Allen bolts are a 8mm hex, attached from underneath. Better to do that than remove the ones above. You can do the entire job without raising the car (I've done it), but if it makes it easier to disconnect stuff at trans + exhaust, raise it. I would definitely have it on all 4 wheels when the engine/trans is removed. The lower things are, the safer and more stable they are. As you raise it, you will start to tilt it. Go slowly, make doubly sure everything is disconnected and make sure the trans doesn't suddenly drop its far end against the floor. 3 people is more than enough.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.