RRC transer box / diff: how to test?

I had my (1980) Rangey on the rollers today having the brakes tested, and to my very great surprise, when the front wheels were being turned, the rears, which were on a bed of free rolling rollers, were stationary. Same with the fronts when the rear wheels were being turned.

Is this normal or is something broken? I could swear last time it was done all 4 wheels turned at the same time!

The car was in N and the diff-lock was off and in high ratio mode.

Can anyone shed any light on this? Is there an easy way to test the transmission? It's not making any suspect noises or anything

Thanks!

if the difflocks off then the fornt and rear axels arnt permanantly connected?????