Front wheels spin, rear wheels don't

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.

Have the front axel actuator checked to if it engages the front end. Also check to make sure the front drive shaft is turning. Hope this helps.

first start by bleeding the brakes and at the same time replace the brake fluid. on your rear end run some lucas for rear ends same for the front and see what happens.

Hi Ralph.

I do not own a Durango, but have owned many 4WD vehicles and can offer tips for proper usage.

The "L" and "H" after the 4 and 2 stand for "Low" and "High" ranges. The 2 and 4 stand for the number of wheels that can receive power from the engine and transmission. Most 4WD vehicles only provide power to 1 wheel on each axle (front at rear for a total of just 2 wheels powered) at any given time (but for purposes of discussion, we'll call it 2WD & 4WD, as advertised).

Generally, "2WD" is only offered as a High range and is the same as a "normal" 2WD car or truck. I haven't seen a car or small truck that offers 2L (but I haven't seen a Durango - so I don't know), but generally 2WD traction can be increased easily enough by simply shifting the transmission to a lower gear (From "D" to "2" or "2" to "1", etc.).

4WD is designed to provide additional traction whenever 2WD isn't sufficient. This can be when surfaces are slippery such as sand, mud, snow and ice or, when pulling a heavy load such as a trailer and tires are not gripping the surface well. Shifting from 2WD to 4WD High will provide more traction at the same tire speed. Maximum power from the engine does not come at low RPMs, so in order to get more pulling power from the engine with out increasing speed (or spinning tires), the transmission should shifted into a lower gear. This is especially helpful when pulling a trailer up a wet incline, etc. If 4WD High in 1st gear is still allowing tires to spin or not providing enough pulling power, then shifting the transfer case from 4WD High to 4WD Low will allow the engine speed to increase (providing more power) without increasing the speed of the wheels (reducing the chances of spinning tires).

4WD should never be used while operating on dry pavement. Since tires wear at different rates, and turning left or right slows the inside tire and speeds up the outside tire when compared to the rear tires, a certain amount of slip is required. Wet surfaces provide this necessary amount of slip - as does sand, mud, snow, ice, dirt, gravel, etc. You should take the time to see how each selection of High and Low affects engine speed and vehicle speed and how the surface and any trailer further changes traction. With a little experimentation, you'll see how it works and be able to choose the right range with little thought.

Don't forget to have the transfer case & front differential fluids checked and changed as per the manual. Neglecting this simple service intervals can leave you stranded when you need 4WD and can be very expensive to repair.

I hope this helps & good luck!

Check and make sure the transfer case is adjusted right If the front end was broke you would know it. Jack up one front wheel and put it in 4wheel drive but not lock and see if the front drive shaft turns if it doesn't you need to adjust linkage or if it's electric make sure the signal is getting to the transfer case. If it only locks front and rear jack up one rear wheel also and do the check. Most people with 4 wheel drive don't know they have two wheel drive One in the rear and one in the front unless you ordered a locking dif from the factory they don't come this way. Then you would have 3 wheel drive

Your front differential is what's called an "open" style. It's exactly the same as any differential found in any vehicle with non positraction rear wheel drive. In that type of diff, one wheel is always connected to the driveline through the small spider gears inside the carrier. When you are driving and there is power being applied through the driveshaft, power goes to the wheel with the least amount of traction, which is actually a bad way to do that but it seems to work fairly well except on ice or in mud.
Positraction differentials put fairly equal power to both wheels but you can't use them in the front end because they would make steering difficult. When you are cornering, the wheel on the outside of the turn needs to turn faster to keep up. A posi makes that difficult, a "locked rear" makes it near impossible. That's why you don't see them except in specialized off road vehicles (not in the front anyway).
The component that makes your front diff move the vehicle is the transfer case. On many GC's they use a quadratrack unit. That kind used a heat sensitive fluid coupler inside that locks up when the rear wheels start to slip. Those units can be identified by their shifter which only has three positions. Technically it's always in 4 wheel drive but it only comes on during slippage. The other manual kind has four positions and is engaged manually. Some early Cherokees (not GC's) and many wranglers use a vacuum diff lock up. So unless someone put one in there (lots of mods would be necessary) you have a normal open diff there and that's just how they act when off the ground.
If you cannot turn the wheel assembly at all, then there's a high probability that the hub bearing has frozen or the brake caliper piston is stuck in the applied position.
One interesting fact is that no vehicle is really four wheel drive...most only have one wheel in front and one in back actually moving the vehicle. If you are equipped with a rear posi diff, then essentially you have 3 wheel drive (with the exception of modified vehicles as I mentioned).

I have a 93 legacy. Subaru's always run in front wheel drive until a sensor tells the computer the front wheels are not turning the same speed as the rear wheels( spining on ice or sand etc.). At that point all wheels will be driven though a clutch to the rear wheels. This is not good if the car needs to be towed with the front wheels in the air! This "all wheel drive" can be shut down for towing. Under the hood on my 93, there is an in line fuse holder on the pass. side of car behind the front strut mount. Open the top of the holder and it will be empty, put in a fuse (10 or 20 amp or close) , this completes a circuit and shuts down the rear wheels. I don't know if the your 97 has this in the same place, but it must have one some place. hope this can help you.

The basic explanation of these gears are as follows.
2up/2wd is a basic two wheel drive setting where the vehicle will react as a rear wheel drive. In this gear the transmission will only distribute power to the two rear wheels(best for all around driving with clear road conditions and will give the best fuel efficiency).
4up/4wd is a high speed four wheel drive setting. in this gear the transmission will always distribute power to all four wheels and will allow you to drive at higher rates of speed( good for poor road conditions when ice and wet roads are a moderate risk).
4dwn/4lo is a low gear four wheel drive setting where again the transmission will distribute power to all four wheels but will limit you to a low rate of speed(good for really rough roads and severe weather or very poor traction conditions).
auto gear selection is basically a all wheel drive setting, where the transmission will use a primary setting of rear wheel drive gearing until the vehicle slips or looses traction on one of the drive traction. as soon as the transmission detects a difference in wheel speed between the two rear wheels, at which time the transmission locks up the front differential turning itself into a four wheel drive, until the wheels have regained traction and remain spinning at the same speed for a set amount of time, at which time it will then unlock the front differential at return to a rear wheel drive setting. this is a good all around gear but will cause you to get slightly less mpg/kpg then a 2up/2wd gear would. i hope this helps

If the Tires wont spin then it isnt locked in.
If it really is engaged like you think it is and they dont turn then something is broken in the differential. If that was the case then it should be makeing lots of noise.
Now it is very very common for the electro-mechanical device that engages the the 4wheel drive at the differential to go bad. If you look at the front differential you cant miss the 4 wheel drive actuator. It has a couple wires that come out and plug into the wiring harness.
Usually if this part fails I understand the 4wheel drive indicator lights wont come on? I could be wrong on that. My sub is 3 years older and that was the case with it.

You have to have your front hubs locked in for four-wheel drive to work