The terrano can only be used in 4x4 in traction-loss situations. That's what's in the manual. This means snow, sand, mud, ....... It says DO NOT engage on hard surfaces. Our winters are probably not like in Finland. Frequently whe have snow which only covers parts of the tarmac. You can have 70/80 metres of tarmac and then 50 metres of snow, depending on the houses, wind, etc....... When driving on these roads it probably isn't safe to engage the 4x4. When you drive into the snow the rear traction can be nasty. The same on some motorway junctions in rainy conditions. We frequently have to turn almost 360° downhimll to get onto the motorway. I have to be VERY carefull or the Nissan has loads of oversteering.
The same situations with the kangoo were a dream. On those junctions I tried anything, nothing to put him of his track. The same in the snowy conditions. I could drive at 80 km/h from no snow into snow, never moved an inch.