Four wheel drive behavoir

The warning not to use 4WD on dry pavement is especially important when making sharp turns as went turning into a parking space.

When making a tight turn, the front wheels have to travel farther than the rear ones in the same period of time hence they have to turn faster. Since the transfer case has the front and rear axles locked together this isn't possible and hence the dragging and kicking.

All Wheel Drive cars and SUVs eliminate that by adding a center differential that allows the front and rear wheels to turn at different speeds while still receiving power.

Glen

The front diff will be an "open" diff, therefore no lock. It will be engaged by the transfer case so it will get power and transfer that to the front wheel that is the easiest to spin. Locking differentials are only used on rear axles by a vast majority of builders and then only for special applications. If you were going to spend a lot of time four wheeling and rock crawling but also needed the truck for regular driving then a locking diff would be for you, but again only for the rear axle. The front tires should never be "locked" together as they must turn at different speeds in order to get through a turn. The rear wheels must do the same thing but the trouble is even greater with a front axle.

What you felt was not the front diff locking but the drivetrain binding. I'm sure your owner's manual tells you to never used 4wd on dry pavement and this is why. The front diff is usually set up about .01 higher ratio than the rear. This keeps the truck pointed front first under power. when driving in a straight line on dry pavement, this doesn't create a terrible problem. Once you turn the wheels, you put an incredible bind on the drivetrain on dry pavement where the wheels can't easily slip the bind off. The Ford will do the same thing in tight turns on dry pavement. You can do some real damage to your drivetrain this way....don't do it with the new Ford :)

-BunnMan

BunnMan, Thanks for the explanation. I was not sure if my co-worker was blowing smoke at me or he was correct. I ordered my F-250 with a limited slip rear differential. I spend some time driving a long hilly, slippery dirt and gravel road. I have been stuck in my car a couple of times. When it snows or rains for any period of time the road is an experience!

Michelle

BunnMan wrote:

The LS will be useful in that situation. For an everyday driver that you will use off road in less than perfect conditions, you can't beat a LS. Practice driving with it though. Open diffs are good for traction on pavement unless you're drag racing and deliver the best mileage and tire wear. LS diffs are great for traction on and off road and even when drag racing. They are also good for regular driving around on paved roads because they will allow some slip (hence the name) when cornering and turning hard. They won't produce the top mileage that an open diff will and will wear tires ever so slightly faster under normal conditions but probably not enough to notice unless you are hard on the pedal. They can get squirly under hard power and/or on extremely slippery stuff though, so be very careful while getting used to it.

God Bless,

-BunnMan

Cool thread thanks guys. :)

OP, a friend of mine has a '65 chevy with the original 4 wheel drive equipment in it and it still works great. He never used 4 wheel drive except when he really needed it and then got out and un-locked it -everytime- after the need was past. It can be done. :)

A guy can screw one of them up leaving the show room if he had a mind to. :)

Alvin in AZ