Sand can vary in different parts of the country. In Florida, you can drive for 300 miles in hard sand and not have any problems. In the desert in Southern California, you would have to deflate your tires to 20 lbs. +/-.
Generally the additional speed and power offered by 4WD high are appropriate for driving in sand. Sometimes, however, low range and drive will work more efficiently in sand and will provide more torque in certain situations. You may need to experiment with both high and low range depending on the surface conditions of the sand you are driving on.
If you get stuck, dig out around the wheels. Use your floor mats under the wheels for traction. If water is available, wet the sand in front of the wheels. This will provide a firmer base. If necessary, air down to 8 or 10 pounds. Rock back and forth and sideways, and once moving forward just keep a good steady forward motion—don’t spin your wheels, as you will only make it worse. Use your hub caps as a shovel if needed.
When driving in sand dunes, be sure your vehicle has a flag on the radio antenna or a mast. This allows four-wheelers on the other side of a dune to know where you are.
If you start to lose traction in sand, mud or snow, turn your steering wheel back and forth slowly. This will generally allow the tires to get a fresh grip and pull you through.
If you lose complete traction, STOP! Do not spin your wheels, as this will usually dig you in deeper.
Remember, speed and power are not the answer. Keep forward momentum at a steady pace.
If your tires start to spin, a slight brake application with your left foot while maintaining throttle pressure will stop wheel spin and maintain forward momentum.
by Mark A. Smith Mark A. Smith’s Guide to Safe, Common Sense, Off-Road Driving
If you deflate your tires to drive on sand, inflate them to the required tire pressure before driving again on other surfaces.