Nissan SUV Range

This mightn’t be too hard to figure out as the GU Patrol used a purely mechanical engagement system for the transfer case and four-wheel-drive system. Unlike newer designs with rotary knobs and electronic control, there’s really not to much to go wrong with the Patrol’s setup assuming it’s a selector problem. Make sure the selector rods are all connected properly and that they’re not binding or loose under the car.

However, if the lever is engaging and the front drive-shaft is not turning the front wheels, then you may have a hub problem. Free-wheeling hubs are great for saving fuel, but when they go wrong, it can often mean the drive doesn’t reach the front wheels. At that point, you have a bigger job on your hands. The same symptoms could also be a result of a broken front differential which is not sending the drive out to the front wheels. Finally, the transfer-case itself may be at fault. If it’s not sending the drive forward, there’s no way the vehicle will achieve four-wheel-drive.

Also, to maximise your chances of engaging four-wheel-drive, make sure the vehicle is stationary at the time and the transmission is in neutral. In fact, this is essential for moving between two and four-wheel-drive in many types of off-roader.

If the problem occurred immediately after you replaced the carpet and seats, I’d say there’s a very good chance you’ve unclipped a wiring plug or connector to remove the interior, and failed to reconnect it afterwards. A lot of modern cars have airbags in the actual seat (the side airbag usually) and the wiring often runs under the seat.

The best move would be to remove the seats again and check for loose wiring or wiring or connectors that have been damaged of misplaced in the process of the interior’s removal. But before you touch anything under there, disconnect the car’s battery. That ensures you won’t have an accidental airbag deployment that could injure you while you’re working in that space.

This sounds awfully like badly worn transmission. The Dualis in automatic form used what’s called a CVT. Instead of gears inside the transmission, the CVT has pulleys and metal belts that vary their relationship and, therefore, create the various 'gear ratios' the car needs.

When these pulleys and belts wear, they can start to make the noise you’re reporting. And, just like your car, it will get noisier as time passes. Unfortunately, you’re probably looking at a transmission overhaul or rebuild. If you continue to drive it as it is, you’ll almost certainly do more damage, although it sounds like the real damage is already done.

Take the car to a transmission specialist who will be able to accurately diagnose the noise and take it from there.