diff lock problem

well lads, new to landrovers but i have a good deal of mechanical experence, we have recently bought a 94 land rover defender for use and abuse on the farm, just wondering if some1 can help me, we recently got stuck in the snow and ice with a load on behind, just popped the difflick lever over and thought aw sure a land rover lock all four wheels and shell grip on the cleared bit of road next to the hedge, but she just spun the front and back wheel on the snow side.

what im wondering is, do landrovers lock all four wheels?
and if they do, what would be wrong with mine that it doesnt do this?

all help appreciated

it dont work like that.

well how does it work?

diff lock only locks centre diff meaning both axles are driven ,but axle diffs have no lock unless you fit one so will stand still if a wheel front and back can spin

aww rite, thanks for clearing that up, are the axle diffs hard to install and do they have any disadvantages?

detroit locker for rear approx £550 inc vat detroit truetrac for front approx £470 inc vat are the easiest ive fitted