Towing a vehicle is very dangerous and requires a highly responsive and experienced driver to do so, yes towing has requirements. In Pakistan towing is considered to be every mans game and the dangers are overlooked.
When you tow any sort of vehicle with another it matter unlike how some people think it doesn't. A surf weighs 1.5 tons approx, so if you tow it you'd be adding that much weight in every aspect to the vehicle which is primarily towing the dead vehicle. In a normal situation when you brake it takes time to stop, lets say a vehicles weight is 2 tons and takes 30 seconds to stop from 60-0, if you add another 2 tons behind it, it will take twice the time to stop. This also means that you need twice the stopping power too as well.
Also you cannot tow a surf with vehicle which has less power than the surf. You would need a vehicle which is twice the power of the surf and you'll have to see the manufacturers maximum towing specs. In large size SUV's the maximum dead weight you can tow is 750-900kgs. If you the towed weight is braked it can go up to 3 tons. Braked means that the weight being pulled has its own brakes and is actually connected to the vehicle which is towing. So when the towing vehicle brakes the weight brakes as well.
If you simply put in a rod and start pulling a surf with any vehicle you'll either end seriously damaging the vehicle and when you brake you might end up with towing vehicle and the weight going seriously going out of control.
THe best way to tow a 4x4 over long distances is to get a 16 feet trailer with a 2 ton axle with brakes actuated by a separate master cylinder which in turn is electronically connected to the towing vehicle's brake pedal with a pressure sensor. Some thing like below.
Keep in mind to tow a Surf on a trailer you need a 4.2 Turbo Diesel Land Cruiser at least to tow safely and effectively.
Quick tip, never tow anything which is more than 1/4 of the towing vehicles weight when the weight is not braked and never tow more weight than the towing vehicles original weight in braked conditions.
And for the record if you want to tow something with your surf you do not need to engage the 4x4 at all as it only distributes the power to all four wheels and not increases. in 4x2 the power is only transferred to the rear wheels and in 4x4 to all the wheels. When you are towing something the weight is on the rear wheels typically which results in better traction any ways.