Hi Gus, First things yep you have an AWD car 40% of the power going to the front 60% to the rear unless the viscous coupling oil is heated via the friction of a spinning tyre. as this is a pre 2004 car this uses the Land Rover Freelander system. some of the parts are not the best, I would say in the first instance to get the car up in the air and check the drive and propshafts for wear and exessive play you will need cv boot kits if not careful here but if you manage to do it without tearing the cv boots then use tie wraps to put them back on. as the noise is constant this would point to either prop or driveshaft failure. also check the rear diff and change oil if not already done so. if none of the above resolves the issue then your looking at a new transfer box at the very least you can get these crated or from ebay, my choice would be a crated post 2004 from dealer. although this is doubtfull due to the fact that no mention of crunching through gears which would point to gearbox\transfer box issues.. my guess would be prop shaft and or one of the four driveshafts have failed, which is not un common in any car with 130K on the clock, also remember to change both sides as they both have done the same mileage