centre diffs are a known problem with them,remove the front prop and try again
Spot on apart from the actual problem is with the viscous coupling in the centre of the the prop they are only good for 70k the viscous fluid thickens and you lose the 'slip' which then loads up the diffs and damages them and the rear diff mount.No front prop on a Freelander. It's basically a modified Rover 25 type gearbox - ie fwd with PTO to rear. You can remove the rear prop and drive with it just as 2wd.
the viscous coupling in the centre of the the prop they are only good for 70k the viscous fluid thickens and you lose the 'slip' which then loads up the diffs and damages them and the rear diff mount.
You wont want to buy a LR one they are a 'bucket of sand' or slightly morenew VC next year!
IMHO the main problem with baby hips is driving with unequally worn tyres you should never fit just two new on one axle it hammers the VC they should be all changed together and swapped around regularly.
That fact is not in the h/book AFAIK,
change front prop if as you say it's going round like an egg well drive shaft,
rover 45/25s suffered with same type of vibes caused by inner cv joint and drive shaft running out of centre
note i also said driveshaft the op refers to it as a front propFreelander doesn't have a front prop shaft.