EXPLAIN THE DIFERENCE BETWEEN THE FRONT WHEEL DRIVE AND THE REAR WHEEL DRIVE

the rear hubs on a front wheel drive car are removed in the same manner as a rear wheel drive car with no front wheel drive
in effect the car is reversed on the chassis all procedures are the same

Elaine,

not work, do tell what makes you think it dont work (a lamp) or tires slipping or dead tires. (by tires mean that and traction)??????????

what mode fails, of the many, and where.???????



first off, we dont know what your tires are touching.

on road, or off road. pavement or ICE or snow.

that matters big time . (you read manual and match MODE to Road)

your lost operators guide explains all that, right?

eg: how and when to use, 4wd, its all there. I promise.

ControlTrac 4-wheel-drive system



here are the mode. which one , gives you problems.



quote ford with comments.



What are the modes, and how do they differ?

(note this is the operational behavior of a 2008 Ford Expedition. Newer and older Expeditions will vary only slightly)



• 2H 2-wheel-drive with high range gearing (1.00:1) Rear-wheel-drive capability,

2-wheel electronic traction control system is enabled



• 4A 4-wheel-drive Auto with high range gearing (1.00:1) Full-time all-wheel-drive capability, ((best on pavement or any time)

Electronically adjusted torque split to front & rear wheels, Electronically variable center differential,

Front driveshaft & rear primary driveshaft allowed rotational speed difference,

4-wheel electronic traction control system is enabled



• 4H 4-wheel-drive with high range gearing (1.00:1) Part-time 4-wheel-drive capability, (not for dry pavement EVER)

Continuous 50/50 torque split to front & rear wheels, Electronically locked center differential,

Front driveshaft & rear primary driveshaft mechanically locked with no rotational speed difference,

4-wheel electronic traction control system is enabled



• 4L 4-wheel-drive with low range gearing (2.64:1) Part-time 4-wheel-drive capability, (off road usage, mostly)

Continuous 50/50 torque split to front & rear wheels, Electronically locked center differential,

Front driveshaft & rear primary driveshaft mechanically locked with no rotational speed difference,

4-wheel electronic traction control system is enabled, ESC and RSC are disabled



In 4A mode the center differential is electronically-controlled and rear drive wheel bias. The on-board computer monitors for any sign of rear drive wheel slip (loss of traction)

If loss of traction is detected, the center differential is told to send a share of the engine\'s torque to the front drive wheels. It will not let the front driveshaft turn at the same speed as the rear driveshaft.



What about traction management?

1997-2002 model Ford Expeditions offered an optional limited-slip rear differential (LSD). A conventional open rear differential was standard along with the conventional open front differential and the electronic locking center differential.

comment with out LSD, one tire can spin, on say ice.

but the other 3 tires dont, in full time.

Hi,
Yes, this is normal while in four wheel drive on pavement.
I will try and explain why.
In four wheel drive the front and rear drive axles are linked together by a chain in the transfer case and gears in both axles. This is a direct link with very little play between the front and rear axles.
When cornering a rear wheel will spin faster, or slower depending on the direction of the turn. this causes a binding in the drive line because the drive line wants all the wheels to turn at the same speed. So the wheel "skipping" going in reverse, is the drive lines way of compensating for the different speed of the wheels turning.
Never should a four wheel drive be used on dry pavement. I could cause a break in one of the drive line components. On a slippery surface , snow, mud, gravel, grass, There is enough slippage in the surface to aloow the driveline to compensate for the different speeds of tire rotation.
So do not try at highway speeds on dry pavement.
Your four wheel drive system is working just fine.
Wayne

Depends on the model, if it is all wheel drive it should have AWD on the back window.
The Honda CRV uses very smart technology to have AWD. Let me explain it simply. The CRV is essentially a front wheel drive car, but there are sensors mounted on all the tires that sense slipping. If the computer determines the wheel is spinning faster than the other ones, it uses hydraulics to engage the rear end differential and presto..All Wheel Drive. You do nothing, no switches, no levers, the computer does it all for you. If it is indeed AWD, you can look under the car to see if you have a driveshaft going into the rear differential (axle)

Please vote if this helped! Thanks, Mike

you can tell by looking underneath the vehicle-if it is rear wheel drive (primary) the rear axle will have a 'pumpkin' in the center of the rear. I do not know of any 4wd that is primarily fwd-so I would think yours is rwd.

Generally, trucks, vans and large cars with big engines will have rear-wheel drive. Smaller, economy and compact cars are most often front-wheel drive. But you don't have to guess which one you have - find out for yourself.
jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); }); Instructions

1. Understand that front-wheel drive means the power from the engine and the transmission goes to the front wheels; rear-wheel drive means the power goes to the rear wheels. Four-wheel, or all-wheel, drive means all four wheels are powered.
   

2. Open the hood.
   

3. Find the front of the engine. The front of the engine is always where the belts are located.
   

4. Look to see if the front of the engine is by the fender (side of the car). If so, then you have front-wheel drive.
   

5. Check to see if the front of the engine is by the radiator and the grill (front of the car). If so, then you have rear-wheel drive.
   

6. Look under the car near each front wheel. If you see an axle with a rubber boot (called the CV boot) on either end going into the wheel, then you have front- wheel drive.
   

7. Look under the car between the rear wheels. If you see a large, metal, pumpkin- shaped thing (it's called the differential) with two axles coming out either side, then you have rear-wheel drive.
   

8. Check both under the hood for the position of the engine and under the car for the axles to be sure, because not every car follows the rules for engine position and front- or rear-wheel drive (see Tips below for examples of cars with variations on this rule).
   

Good Luck

I was under the impression this was a front wheel drive vehicle. There would be no Drive shaft in that case. If it is rear wheel drive you need to look at both the front and read connecting Joints and find the one with bolts on it and remove the bolts then the joint itself. The only other way would be to use a punch to punch them through. Get a Haynes repair Manual on your vehicle and it will explain the procedure in detail.

Have them check the universal joints, front and rear, as well as the two on the front shaft if it is a four wheel drive model, the CV joints on the front axle if 4WD, the drive shaft(s) for straightness, mud in wheel recesses, and the rear end and front differential "chunks."

It's easier to do than explain and would take around 2-2.5 hrs.if rear wheel drive. Front wheel drive about 3 hrs.tell me what you have. What area do you live?

It possible that the drive shaft need to be turn 1/2 turn and re installed, or the balance weight is missing from the drive shaft.