Re: scared to death
A very interesting thread. My advice is, carry a couple of strips of old carpet, 8 or 10 feet long, if you frequent a ramp where traction can be bad. Put them in front of your drive wheels if that is necessary. Outdoor or boat carpet is good for this. A bag of sand or fine gravel, or even mulch or kitty litter, can come in handy also to sprinkle for traction. Oh, and keep a tow rope -- the next guy waiting will be only too glad to pull you out so he can use the ramp.
A little primer on traditional or part-time 4WD as in American pickups, for those who are unfamiliar: while the book says don't use 4WD on dry pavement, the evil that is sought to be prevented is that of causing windup in the drivetrain by going around turns (one wheel then revolves faster than the other, and because it is difficult for the tires to slip on dry pavement, the effect is to torque the drivetrain). Going in a straight line, and not very far, on dry pavement will not hurt the drivetrain. Indeed, going around a turn or two probably wouldn't do it any harm (although you'll hear it protesting), you just would not want to make a habit of it, just like you would not want to make a habit of shifting without the clutch.
Many trucks these days have automatic locking hubs in the front that engage or disengage the axle shafts to the front wheels with a set of dog gears when you shift in or out of 4WD. Others use manual hubs, although you see this less often anymore. You can drive around in two wheel drive with the front hubs locked in on a truck with manual hubs. The drivetrain to the front wheels is not powered because the transfer case is not engaged to 4WD, so what happens with the hubs locked is that the unpowered front wheels, turning as the truck moves, turn the axle shafts and the driveshaft back to the transfer case, where the driveshaft is not engaged. It cause a little drag to leave the hubs engaged like that, because you are turning the unpowered drivetrain back to the transfer case, but it doesn't hurt anything to do it. Thus, if I had a truck with manual hubs, I would lock in the hubs when I left the house on a snowy morning and go in and out of 4WD during the day as needed, and not bother with getting in and out to lock in the hubs.
More sophisticated part or full-time "all wheel drive" systems, such as are found on GMC pickups and as an option on Jeep wagons, and on many cars, use either a center differential or a viscous coupling to eliminate the problem of drivetrain windup, and so can be used on dry pavement.
