Hi everyone. I have a 2000 Exp with 159,000mi. About a month ago I was just driving slowly into a parking lot and noticed it suddenly felt like I has turned the 4x4 on. Turned the engine off and back on and the problem went away. Then last week it happened again - just noticed the sound and drag that the 4x4 makes when turning a corner. Again, turned the engine off and back on and it fixed itself. On a monthly basis I spend the weekend in 4x4 low and know it works fine other than the mystery activation. My truck is trying to tell me something but I'm not sure what it is - can someone translate please. Thanks much!!

 

...oh and by the way; no 4x4 light, no clicking, and, of course, I'm not touching the switch!...

 

Auto 4 wheel drive switch position?

All all 4 tires the same size? and of equal wear.

 

Yes. Nothing has changed with the tires. Rotate regularly and they all look the same as far as I can tell.

 

heterodox1 did u find out the problem,my 01 Expy did the same thing at slow speed in a parking lot,4x4 light came on,i turned off the truck and has not done it since,but i am curious as to why.i was only moving at 10 mph when it happened.Hope its nothing to $erious.

 

The wear or inflation of all 4 tires could be part of your problem...especially during turns.

 

Thanx Baitguru,it actually happened while turning.I"ll check the tires.

 

the vacuum solenoids that control the 4x4 switch are starting to go bad. Either that or the vacuum motor that sits on the front axle. Thats what happened with mine.

 

""""""Hi everyone. I have a 2000 Exp with 159,000mi. About a month ago I was just driving slowly into a parking lot and noticed it suddenly felt like I has turned the 4x4 on........"""""

I have same issue with mine right now and i would like to know what was your fix for that issue? If you did it your own any guidance on what to look for or where to buy the part ?

Thanks

 

First check the vacuum shift actuator which is the part that actually shifts the diff into 4 wheel drive. Its also called the vacuum shift motor.Unfortunately it is under the car. next you will have to check the solenoids that turn the vacuum shift actuator on....They are located behind the battery at the firewall. Mine went bad because water got in them, dripping down from the winshield. there are 2 of them, one to shift on and one to shift off.

 

its easiest to check the pressure in the system between the three of them w (vacuum motor, 2 solenoids) with an air pressure meter of some kind. to check for leaks or figure out the one that isnt working. I found the instructions somewhere online either here or Ford f150 forums or somewhere, I cant remember but it is a common problem

 

One more thing... I got tired and replaced the whole<cite></cite>thing with a manual cable. Its called a 4x4 posi lock. you can find it here <cite>www.4x4posi-lok.com so no more solenoids and vacuum motors. I just do it manually</cite>

 

I'm new here, but my 99 4x4 EB Expy is having the same problem; I have about 135k miles on it.

When I first raised the issue to the local dealer, they said the problem was caused by my tires (they were BFG AT KO at the time) and suggested getting new tires. I was ready for new tires anyway and replaced with some Toyo tires from Big-O [recommended by the guys at Big-O] -- I still have the problem with 4x4 engaging from time-to-time.

Maybe the 4x4posi-lock system is in my future... I dunno.

 

I thought that 99 and 2000 did not have the diff shift only the transfer case shift. MIne did it once while turning and going very slow, but not since.