My '92 XLT 4x4 wont engage

[travis_broyles]

i have a '92 xlt 4x4. i got it about 2 weeks ago and the 4x4 wont engage. i cant find anything for it in my chilton's so i was looking for a place to start. could it be the dash switch? any readings i can check with my multimeter to verify? or what else are common problems with this system?

 

[DeRocha]

Hi Travis and welcome to the site.. Your question is very common and most often asked by new members with 1st generation explorers (91-94). Check out the shift motor repair thread for lost of info and pics on the 4x4 engagement system. In most cases the system fails because a tiny stop bumper has failed and allowed the geared sensor to move slightly outside its operational range. Check out the thread and let us know what you find.

 

[cws4c]

'94 Explorer XLT, 4X4 High range works, Low range doesn't

I am new to forums so I hope I am posting this right.

I have an electronic switch that I can press to engage 4x4. When I press 4WD High, the light comes on and I hear it engage. When I press 4WD Low, the light doesn't come on and the 4WD doesn't engage.

I have tried changing the switch (with one from a junkyard), shift control module (ebaymotors), speed sensor (junkyard), but nothing has worked.

I changed the transfer case fluid and lubricated the tranny shift cable. When I changed the fluid, it was black and overflowed out of the transfer case. The front automatic locking hubs were professionally replaced about a year ago.

What do you suggest.

 

[Tbars4]

read post above by derocha and click on shift motor repair...it will lead you to a thread that is full of the info you are looking for...

 

[dkitt10]

my 4x4 switch would allow 4x4 to engagel...and lioke a couple above my low wouldnt work...but popping it into neutral allowed it to enter low with out any problems what so ever...not sure if this is just me or all 4x4's because im not familar with 4x4 systems yet....

 

[Tbars4]

whenever you switch into 4x4, swith into hi or low, it is always best to lock the hubs if they are manual,put the vehicle in neutral, then engage into 4x4, again, if you switch into hi/lo, come to a stop, put your vehicle in neutral, then switch...remember to never drive on pavement in 4x4, not a good thing...

 

[mikeinri]

This is very simple. If you have an owner's manual, it's covered in there.

It is 100% normal (by design) for 4x4 High to be engaged/disengaged at any speed, in any gear. Obviously, it is recommended that this only be done at speeds less than 45 mph or so for safety reasons. It is "4x4 on-the-fly."

It is also 100% normal (by design), IN FACT REQUIRED to have the truck stopped, and in Neutral (Park might work) for the 4x4 Low to engage/disengage.

As mentioned, if you have auto hubs, you're all set, just push the buttons as described. If you have manual hubs (very rare as stock, many people change autos to manuals later), you have to get out of the truck to lock them in before the 4x4 will drive the wheels (the axle shafts will turn, but they won't be driving anything).

Having said all of that, if the truck is new to you, it behooves you to try this out before you really need it, to make sure everything is working correctly. Again, don't do this on dry pavement, good way to break stuff...

Hope this helps.

Mike

 

[DeRocha]

As mike has already stated the 4x4 low button will only allow the T-case to shift into/out of 4x4 Low when the T-Case is already in 4x4 High, the Transmission is in Neutral and the speedo reads <3mph (and the clutch is in on manual transmissions). This precaution is because the tremendous force of 4x4 low will destroy the transfer case if you were to accidentally shift it in while traveling at high speeds.

 

[cws4c]

I tried engaging the 4X4 Low Range in Neutral and it still didn't work. Should I try the shift motor repair suggestions above by checking for a deformed plastic bushing?

 

[cws4c]

Sorry for listing twice in a row...

 

[DeRocha]

I tried engaging the 4X4 Low Range in Neutral and it still didn't work. Should I try the shift motor repair suggestions above by checking for a deformed plastic bushing?

The shift motor repair is generally for non functioning shift motors (yours appear to shift fine into 4x4 high). Do you have an automatic or manual transmission? If manual then you will also need to put the clutch in for the shift to 4x4low..

Does the 4x4 computer in the rear hatch make any noises when you press the 4x4 buttons? When was the last time 4x4 low was used?
(click image for large pic)

What is the tranny shift cable you lubricated?

 

[cws4c]

4X4 Shift motor plastic bushing was not the problem

I opened up the 4WD shift motor and checked the plastic bushing as suggested. That was practically in perfect condition.

My explorer is an automatic. I bought the car in the fall of 2004. I don't remember the 4WD low range working since I've owned the car. I don't know how to describe the cable/lever that I lubricated. It has been a while. It is attached to the transmission and may not have anything to do with the 4X4 problem. It is more of a metal bar that shifts something in and out of gear.

 

[cws4c]

4x4 computer in the rear hatch makes no noise for Low Range

When I press the 4x4 high range, it engages properly and I hear the 4x4 computer in the rear hatch make a noise when I turn it on and off. When I try to turn on the low range, I hear no noise at all. I remember trying to replace this computer with one that I bought off of ebay motors (used). It didn't solve the problem at the time, but maybe the replacement was faulty. I also don't remember if either of the 4x4 high or low worked at that time.

After I tried the computer replacement, I eventually had the automatic locking hubs replaced, which may have caused the high range to start working. Again, I can't really remember exactly when the 4x4 was working and not working. Any suggestions?

 

[DeRocha]

I had a thought.. is the truck in 4x4 High when you press the 4x4 Low button?

The 4x4 Low button will only work if the T-Case is already in 4x4 High.

 

[cws4c]

Thanks DeRocha!!!

Wow. I feel like an idiot. I did what you said, engaged the high range, then simply pressed the button for the low range and it worked. You made my day! Thanks again.

 

[SensRanger]

Bah! I was hoping when I got to the end of this thread the solution to my woes would be revealed....but alas cws4c's problem was more simple than mine.
I have the same problem, 4x4 high works perfect, no 4x4 low. It used to work so I know I am trying to engage it correctly. The shift motor works for 4 high and no issues from the t-case. I thnk the problem is electrical, ie. the computer does not sense the right "conditions" for 4 low operation.
I have tried the following:
- replaced the transfer case shift relay module (aka 4wd computer)...no change
- replaced brake pressure switch (to fix broken cruise control)...thought this might impact 4 low operation, but nope, no change
- had trans shift linkage cable replaced and range sensor inspected...supposedly was fine, but sometimes will still not start in Park without jiggling the shifter, and sometimes the back-up lights do not come on in R...so I am not convinced my range sensor (DTR or MLPS..not sure which one I have) isnt faulty

No issues with the speedo so I assume the speed sensor is working ok...

Any other ideas? I am doubting the 4x4 range selector switch failed but you never know i guess.

Thanks

 

[Bwana Bob]

It may be dirty contacts on the position sensor for the shift motor, or the switch that senses if you are in park or neutral.

Bob

 

[DeRocha]

...sometimes will still not start in Park without jiggling the shifter, and sometimes the back-up lights do not come on in R...so I am not convinced my range sensor (DTR or MLPS..not sure which one I have) isnt faulty

No issues with the speedo so I assume the speed sensor is working ok...

Any other ideas? I am doubting the 4x4 range selector switch failed but you never know i guess.

Thanks

After engaging 4x4 High try jiggling the shifter while pressing the 4x4 low button.. of course you don't want an issue where you get stuck in 4x4 Low and can't disengage it..

 

[Stic-o]

at least yours works...

I push the button on my B2, and all get is a clicking under the dash. But 4x4

 

[mikeinri]

"the switch that senses if you are in park or neutral"

This used to be called the Neutral Safety Switch on some vehicles, if that helps.

My money is on this being your problem, especially with the starting problems you're having.

Also, keep in mind it may not be a component, but a wiring problem (intermittent short, etc.). Parts can be easier to replace than testing wiring, but the cost can add up if you're just blindly part-swapping. (I do know that sometimes there is little choice.)

Mike