I have a 2002 ford expedition and it slips into 4 wheel drive every now and then. It happened in July and then again tonight?

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.

There may be some loose whires going into your transfer case which will disable the 4x4 light, your speedometer, and cruise control. And if u were in 4wd when a wire became loose then it will stay in 4wd until fixed. Also check any vaccum lines not connected.

If your vehicle is a 4 wheel drive, than you are probably driving in 4low or 4 high on dry pavement. Put it back in a4wd (automatic 4 wheel drive) position and this shaking when turning should stop.

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The system may still be stuck in 4x4 even though you have turned it off and it appears to be off. If it is still in 4x4 it should difficult to make tight turns on dry pavement due to the vehicle wanting to buck and **** as it tries to turn while all 4 wheels are trying to rotate at the same speeds. The driveline may also whine if you are driving in a straight line on a dry/hard road surface.You may have to have the vehicle lifted up on a hoist so it can be test run with all 4 wheels of off the ground to determine if indeed it is still stuck in 4 wheel drive. I see this type of problem with 4x4's several times each winter [not just Fords] so it can happen. Good luck, hope this helps!

If you can't find the 4 X 4 switch, then your expedition is probably All Wheel Drive and it will not have an on or off. If it is "all wheel drive" it is like it is in four wheel drive all the time and will kick in when it feels a wheel slip. Check your owner's manual and you will probably find that it is all wheel drive. Hope this helps.

165 foot pounds is the spec for the axle nut

you need to check the front axle U-joints out by the wheels,they start to bind up when you make sharp turns,the U-joint won't flex and will need replaced

Possible solution..Expedition uses a vacuum solenoid on the firewall that controls vacuum to the 4-wheel drive actuator. Vacuum "unlocks" the 4-wheel drive, so you may have a leak in the line to the actuator so the 4-wheel drive is always on. Seems backwards, I know.

solenoid switch that engages the 4WD more likely will need replacing. fairly cheap to fix replace.