The geartrain on the 8265 DOES get wound up due to no centre diff. I believe that the model is accurate though, and that the real thing lacks a centre differential.
I drive Land Rovers offroad quite regularly. The centre differential is always locked once offroad (where you get enough slip to relieve any tension), but having it locked on the road causes damaging gearbox wind-up, and increased tyre wear.
Clearly this isn't a problem on A) Dirty great front loading mega-shovels used in slippery quarries and B) lego models of the same. A little slip is expected.
You would never have an AWD road car without a centre differential as it would understeer like an absolute animal, and understeer feels like failure.