Lost 4 wheel drive

[Cire92]

We have significant snow fall here in the Willamette Valley (Oregon), which is uncommon. The 92 Explorer would not engage in 4 wheel drive. The light on the dash and beside the 4x4 button works, clicking noise in the rear left side. The transfer case does engage in 4 wheel Low, without 4 wheel drive, which makes me think that the actuator motor is working, or could the motor only partially work? Could it be my manually locking hubs (swapped out the stock hubs for a set of Warn manually locking hubs)? Need help, would like to take my wife and three kids to the grandparents home for my birthday dinner, but I want Explorer to engage in 4 wheel drive.

 

[Cire92]

I have read the “Fixing the Transfer Case” thread, http://www.glue.umd.edu/~singletn/web/pages/tcase.html, but my problem is not quite the same it seems because of the light on the dash works and 4x4 low engages with out the 4 wheel drive.

 

[Alec]

Really stupid question:

Are you exiting the truck to manually engage both front hubs?

I'm asking because if 2lo engages it kinda rules out the tcase to me, dunno. Is the front driveshaft turning? That will help us narrow it down. (try to see with both hubs locked and unlocked)

 

[MrShorty]

Originally posted by Alec
Really stupid question:

Are you exiting the truck to manually engage both front hubs?

I've made this mistake before. Somehow I had one hub in lock and one free. Couldn't figure out why I didn't have 4WD. Upon closer inspection, I found the problem.

 

[Cire92]

I have to exit the Explorer to engage the hubs. I have checked them and they are both engaged. How would I check to see if the front drive shaft is turning? May sound like a stupid question but I guess I am stupid when it comes to checking the front drive shaft.

 

[Alec]

put it in 4wd and drive slowly and have someone watch.

Dunno, maybe you could lift the truck up, in neutral and 4x4, and see if everything turns together; but that's much more difficult.

Like I suggested above, try it both with and without the hubs.

 

[DeRocha]

First off how are determining 4x4 low is engaging? Do you hear/feel the drive shalft coming up to speed with a slight thump noise, or are you just seeing the dash light up? If 4x4 low was engaged you would feel a ton of torque wind up when turning on drive pavement. I also believe you cannot access 4x4 low unless you are already in 4x4 high.

 

[Cire92]

Four wheel low is engaging based upon the noise made, Thump noise, when engaging and the obvious reaction when driving the Explorer. Ton of torque and at 25 miles per hour the Explorer is at about 3000 rpm when in high gear, OD.

 

[Cire92]

Ran the processor board check (the one in the rear left access panel next to the jack and rear windshield washer container) when pushing the white square button on the bottom edge of the processor board the LED right next to the button flashed.

 

[DeRocha]

This is weird. I would have thought it was your shift motor, but it appears to be working ok. If you are able to engage 4x4 low then the shift motor is working. The shift motor is actually 2 parts. The worm driven motor and the geared position sensor. The Position sensor is notorious for getting "lost". This occurs because the plastic stop inside the sensor breaks apart over time and allows the sensor to travel slightly outside its operating range. If this happens then the the 4x4 computer module next to rear washer fluid reservoir will have no idea what position the T-cases is in and will shut down and do nothing. But if you're able to switch into 4x4 then I'm guessing the 4x4 module isn't lost and switches to low just fine. I would next suspect the dash 4x4 button as being defective, but you have indicated when pressed it does cause the relays to "click" in the rear module.

Things I would try in order of ease:
1) Tap on the shift motor position sensor cover (circle cover with wires sticking out). The purpose is to try and jiggle the internal connectors into making better contact. Sort of like needing to repositioning jumper cables to get better contact.

2) Loosen the shift motor position cover and move it slightly 1/16" or so left or right. The Purpose is like above, with the addiction of correcting the sensor position if the plastic stop has been destroyed/worn.

3) Replace the Dash 4x4 switch. Get once from a junk yard for cheap $$.

4) Remove shift motor and clean as instructed in EDU site.

Behind the scenes: The Electronic-Shift 4X4 System uses a control switch, module, magnetic clutch, shift motor, speed sensor and transfer case position sensor. It can be shifted from 2-Hi to 4-Hi at any speed and shifted to 4-Lo at 3 MPH or less. When you select 4-wheel-drive on the control switch, the module uses the motor to shift the transfer case. It also energizes the clutch to bring the front drive shaft up to the same speed as the rear drive shaft. Once the front and rear shafts reach the same speed, a spring-loaded collar locks both shafts together inside the transfer case, completing the shift to 4-Wheel-Drive.

 

[Cire92]

Check the front axle with a mirror and found the following:

>The axle turned when in 4x4 hi with the hubs locked and unlocked.
>The axle didn’t turn when in 2 hi and the hubs locked in and unlocked.

This leads me to believe that the hubs have failed. Tried to find some manual locking hubs at the part store but all the places I have tried are out of stock. Warn is shut down for the holidays. The hubs in the Explorer now are Warn manual locking. One parts clerk stated that it is rare for the hubs to fail. He said that if grease was to get into the hubs they would fail and just a simple cleaning of the hubs would alleviate the problem. I am going to try that and see what happens. Any other advise would help.

 

[DeRocha]

Something is wrong here. You said in you're last post that 4 low works. If it is working you will feel the front end very stiff on dry pavement (is this the case?) If you have a bad hub (with open diff) then both 4Low and 4 HIGH would act the same.

If is very rare that a manual hub goes bad without first subjecting it to some real hard core offroad abuse.

 

[Alec]

Just asking for clarification:

The axles turned and not just the driveshaft? That rules out a problem in the diff.

And what about trying this in lo?

 

[Cire92]

I took out the hubs and found them to have baked on grease in the gears. When placed in Lock they would not engage. After cleaning them up they worked fine. I did find that the gears were very pitted and one spring was broken at the end due to corrosion. I will purchase a new set of hubs or a rebuild kit if they have such a thing.

To answer you DEROCHA, when 4 low was engaged (as indicated on the dash) I only had 2 low. And I have not subjected the hubs to “some real hard core off road abuse." It appears that the grease in the hub, combined with heat, and possibly some dirt, caused the hub to malfunction (extreme build up of crud which prevented the gears to engage). I also believe that I still have a problem due to the build up of grease and the condition that the hubs were in. I swapped the hubs out in August of 2000. Any Idea as to why I had some much grease and possible dirt build up?

And Alec, the axles did turn and I did try this in lo. Thanks for the help. Also, what feed back can you give me regarding the build up of crud and crap in the hub which contributed to the malfunction. Corrosion and pitting was found in the metal of the gears.

Thanks,

Eric

 

[Alec]

Any salty, muddy, flooded, etc driving; where the hubs would be subjected to washing or debris?

 

[CBLAMBERT]

I took out the hubs and found them to have baked on grease in the gears. When placed in Lock they would not engage. After cleaning them up they worked fine. I did find that the gears were very pitted and one spring was broken at the end due to corrosion. I will purchase a new set of hubs or a rebuild kit if they have such a thing.

To answer you DEROCHA, when 4 low was engaged (as indicated on the dash) I only had 2 low. And I have not subjected the hubs to “some real hard core off road abuse." It appears that the grease in the hub, combined with heat, and possibly some dirt, caused the hub to malfunction (extreme build up of crud which prevented the gears to engage). I also believe that I still have a problem due to the build up of grease and the condition that the hubs were in. I swapped the hubs out in August of 2000. Any Idea as to why I had some much grease and possible dirt build up?

And Alec, the axles did turn and I did try this in lo. Thanks for the help. Also, what feed back can you give me regarding the build up of crud and crap in the hub which contributed to the malfunction. Corrosion and pitting was found in the metal of the gears.

Thanks,

Eric

Hubs need to be serviced regularly just like wheel bearings or they will fail. Why would you be instructed NOt to grease them?? this is why they were pitted & coroded...grease prevents the water from damaging the metal...I always have torn the manual hubs down & clean regrease every year or so.

 

[DeRocha]

Hubs need to be serviced regularly just like wheel bearings or they will fail. Why would you be instructed NOt to grease them?? this is why they were pitted & coroded...grease prevents the water from damaging the metal...I always have torn the manual hubs down & clean regrease every year or so.

HUBS need a thin film of grease to prevent rust and corrosion, but no more. Packing them with grease is a big no no as It can hydro lock the hub causing it to fail.

Check out threads like Autohub fix for more detailed info on the hubs

 

[CBLAMBERT]

Thanks for the adding the clarification on that DeRocha...certainly but point being to assume they are fine & be surprised to find a mess after 10 yeas of use is no shocker to me is all I 'm getting at. These hubs are subjected to extreme heat & are sealed with a o-ring..the surfaces must be cleaned & greased regularly or will rot up from salt, water & grit seeming in over the years, not to mention condensation from heat cycles. Glad you found the culprit to your troubles...