SERIOUS BACKLASH NOISE

Have a 2002 Disco 2, when accelerating or backing of harsh clicking noise. Have jacked up one wheel this morning, Universal joints all good, by grabbing front and rear drive shafts can replicate noise. It would appear it is coming from the front of the transfer case but unsure what is causing problem, parts manual would be handy but not on hand.

Any one have the same problem or know what is causing mine.

No Land Rover dealer nearby

Thanks

Now at shop being looked at, will post the solved problem