gear linkage and clunking noise

Hi all, my defender 90 has is in high range with no ability to get into low range as the low range gear lever has complete free movement, i have been told my someone laning that it would be the gear linkage, anyone know if this is a big job and more importantly an expensive one!? ive only owned her for 4 months so as of yet i am not too knowledgeable.
Also when i accelerate or take my foot off the gas there is a clunk noise which otherwise is non exisatant, which from reading all sorts believe to be the UJ's do tou think they just need to be greased or could it be worse?!

Any help whatsoever apprciated.

i would say the clunk is the a frame ball joint.

UJs should be greased as a matter of course. Do it, and see if the noise goes away.

As for the linkage, remove the transmission tunnel (handful of screws) and look at it, its all freely accessible, as ive been doing mine just today!

thanks 4 ur quick response i will grease them as soon as i get home from uni next week and i will have a look at that linkage! ur right a defender will pull anything, even drive thru 2 foot of mud in high range, not bad! regards.