When climbing or descending steep hills you need to know what is on the other side before you venture out there. Always do a route recce to ascertain what it is you will be driving into, before you make the attempt. Once again check your approach and departure angles and ramp break over angle to ensure it does not exceed those of your vehicles.
For descents engage low ratio gearbox and (or) hill descent control (where fitted) then select first gear and line yourself up before the descent starts. Once you have lined up the vehicle, make sure no other vehicles are on the hill before you start the descent. Whist descending, keep a loose firm grip on the steering wheel and DO NOT use the clutch or the brakes. Let the engine do the braking as you descend the hill. Always try to stay parallel with the hill as this will aid stability and lessens the risk of rolling over as you descend. Apply power just before you reach the bottom of the hill and change gear to suit the terrain. If you experience a slide as you are descending the hill, blip the throttle in order to help the wheels begin to turn again. If the wheels are not turning you have lost control. Once the wheels start turning again and you have re-gained control, now back off the throttle until you reach the bottom. The most important thing to do whilst descending a steep hill is to keep the vehicle pointing in the right direction. A speedy descent is often better than going down on your side or roof.
For ascents engage low ration gearbox and the centre locking differential if you have one fitted. You should aim to climb hills in the highest gear possible. This will minimise loss of traction due to too much power being applied to the wheels. I recommend second or third gears for ascending hills. Once again try to keep parallel to the hill in order to aid stability and reduce the risk of a roll over. I f there are ruts already on the ground and they are not too deep for your vehicle you should always attempt to use them if possible. This will act as a guide for the vehicle and help jeep it on course.
Apply power just before the bottom of the hill and maintain it throughout the climb. However, as you crest the top, back off the power a little to avoid going over the top too fast and landing heavily. This could damage the half shafts, differentials and transmission and cause temporary loss of control of the vehicle.
Once the rear wheels are over the top you can then back off the power completely. Be prepared for a failed hill climb and make sure everyone knows what to do in just such an emergency. Do not follow other vehicles up the hill until they have cleared the top. The last thing you want is the vehicle in front rolling back into you out of control