It sounds like there’s not much left to change in terms of belts and pulleys on your vehicle. But did you change the relevant tensioners at the same time? Tensioners run on bearings which can start to seize up over time and kilometres, often contributing a squealing noise that is easily confused with belt-squeal. Also, simply changing the pulley on, say the alternator or the air-con compressor, will not cure the noise if it’s being caused by the alternator or compressor itself.

Other things to check include the correct belt tension and the alignment of the belt (is it running truly between the pulleys, or attempting to run slightly sideways?) Don’t rule out a coolant leak that is getting on to the rubber belt and causing it to squeal.

The refusal to shift from four to two-wheel-drive could be any number of things from an electrical or switching fault to a mechanical failure within the transmission or transfer-case. So that needs to be checked out before you do any more damage to the vehicle.

In fact, the best advice would be to not drive the car any farther at all, because the jerkiness you describe is typical of a part-time all-wheel-drive vehicle that is locked in all-wheel-drive being driven on a normal, or grippy, surface. The need for the inside and outside wheels of a vehicle need to turn at different speeds when cornering, is over-ridden in a car like yours when low-range all-wheel-drive is selected. At which point, what you're feeling is the entire driveline fighting itself and loading up incredible stresses into the axles and differentials. Drive it any distance like that and you'll surely break something mechanical.

The price is on the high side, but the kays are below the average for that model. There have been problems reported relating to cam timing belt failures that have led to major engine damage. I would avoid early Amaroks like the one you are considering and go for a safer option of a Hilux, Navara, Triton etc. rather than tale the risk.