I just limped home in my 4x4 Saff, the car suddenly developed a violent shaking, the gearstick wobbling, the same in and out of gear, it's ok up to about 10mph then undriveable over that speed. I have jacked it up and can't see anything obvious but I don't know where to start looking really.

The shaking seems like it's coming from underneath.

 

propshaft mount come adrift? just a guess. can't imagine anything else would cause that. apart from bent driveshafts

 

Engine mount perhaps - that would explain why you still have it when gearbox is disengaged

Dit it start after a hard launch or gear change, or just normal driving

 

Probably the front prop to the transfer box,had this happen on my xr4x4

 

I'd be thinking of joints first.
tabetha