'02 Ford Explorer going into 4x4 high on it's own...

[DesertCourtz]

I purchased this vehicle used, and while the 4x4 lights on the dash illuminate upon start up, pressing the buttons for either will not light them up on the dash any other time.

I keep feeling the 4x4 high kick in. I've checked the tires and pressure. Sometimes you can hear it, or feel the lurch when it switches, other times not. Though I have noticed that the moment it switches into 4x4 high, the estimated "miles until empty" goes down drastically. So if I look at that, I know whether or not I need to put it in neutral and press the 4x4 Auto button until it goes back to normal.

This is absolutely driving me crazy to not be able to put it into 4x4 when I want, but to have it randomly decided to do so while driving on paved roads/highways/interstates. Anyone have any suggestions?

 

[Mbrooks420]

I’m guessing it’s not in “high” but in auto mode and it thinks the wheels are slipping and trying to compensate to bring both axles up to the same speed.

Will it shift into low if you are in neutral with your foot on the brake?

 

[DesertCourtz]

Okay, please forgive what is likely a very dumb question. But isn't 4x4 Auto the normal mode?

And while I can't tell for sure without the dash lights, it does seem to come on. Or at least I will end up backing out of my parking space a hell of a lot faster than I planned if I put it in reverse and take my foot of the brake. But yes, even on largely flat areas, if I hold the break down in neutral and press the low button, it will then act like it is engaged at least. This is a new car to me, so I don't know what the car SHOULD feel like when everything was working properly, so it is much harder for me to gauge what is happening now that it's not.

 

[Mbrooks420]

Auto is the normal operation. It runs in rwd until slippage is detected, and then it cycles the front axle to try and mitigate the slippage. You should hear it go into low, and it should have a drastically reduced top speed. You shouldn’t run low on any surface with a lot of traction.

 

[DesertCourtz]

Okay. Then yes, I believe it does go into low. The parking lot I'm in is rough asphalt, so there is plenty of traction. I have not attempted to drive it far though, nor attempted to go fast at all, so I can't say for certain.

 

[imp]

Okay. Then yes, I believe it does go into low. The parking lot I'm in is rough asphalt, so there is plenty of traction. I have not attempted to drive it far though, nor attempted to go fast at all, so I can't say for certain.

@DesertCourtz
The 4X4 HIGH lamp illuminates when the key is turned ON to prove out it's working. Upon starting the engine, operation is in 4X4 AUTO, no button pushing needed. Depressing the 4X4 HIGH button at ANY TIME, even with the engine not running, but key is ON, places the vehicle in 4X4 HIGH range, and illuminates the 4X4 HIGH lamp in the dashboard, where it remains until the 4X4 AUTO button is depressed. The vehicle should never be driven on pavement AT ALL in 4X4 HIGH or LOW. If you have a front tire and rear tire of differing diameter, the computer will "think" slippage exists between front and rear, and engage 4X4 AUTO, which is basically 4X4 HIGH, only automatically turned on and off.

 

[Mbrooks420]

That brings up a good point. Do your front and rear tires match brand, model and size?

 

[imp]

That brings up a good point. Do your front and rear tires match brand, model and size?

@Mbrooks420
Being a Simpleton, I like looking at the simple possibilities first. Sometimes luck out, sometimes get called "A.H.", but, that's life! imp

 

[Mbrooks420]

It’s much more often the simple solutions. At work I am constantly coming in and cleaning up simple problems that were overlooked, and blown right by in troubleshooting.