Check the lower engine tie bar bush. They go soft and allow the engine to flop about.
If it's minus the propshafts, then you want to change the IRD oil before going any further. If the oil is full of metallic silver or grey particles, then the bearings are shot and fitting the propshafts will finish it off.
A word of caution. Only release the IRD drain plug, after the fill plug is removed. Also only use a hex (six flats) socket, as the fill plugs are made of soft cheese.