The backlash is probably the sum of a lot of small amounts of backlash, with the major contributor being the centre diff - but I would carefully check to make sure none of it is in propeller shaft U-joints (unlikely) as you realy don't want to have one fail.
However, there is usually a fair amount of slack in Landrover drive trains, and it is usually not a problem. The effect you note is almost certainly due to the combination of the backlash and a dragging handbrake. The dragging can be confirmed by touching it (carefully) after a run or jacking up one rear wheel (chock other three) and turning the prop shaft (brake off, T/C neutral, centre diff unlocked) which should turn freely.
Drag will be caused by incorrect adjustment, sticking handbrake cable, or oil on the brake due to a leaking rear seal (this is the most likely).
Hope this helps,
John
				
			 
			
		 
			
				
			
			
				John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
			
			
		 
	
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