4x4 not disengaging.

[Mildew_Inc]

I've got a 1994 explorer with auto hubs. Every thing works just fine in 4lo. When I try to move it up into 4h it will work kinda seems to slip and not catch Then goes to nothing. It will do the same thing when I put it into 2h. I've replaced the shift motor thinking that was it. Still no go other then 4lo.

 

[murkinstock]

Have you backed up for about 20 feet? If it's not dis-engaging or engaging properly you may want to switch to manual hubs. I've heard they are much more reliable. Don't drive it in 4x4 on high traction areas either. It's very hard on the system as its not designed for it.

 

[Gadget X]

one thing to try is "tapping" on the shift motor with a hammer or something, and then trying to get it out of 4lo. You can take the shift motor off and change it manually, iirc, just don't remember how right now!

 

[murkinstock]

Oh I was confused. My bad, the title put me off. Yeah I would try pulling the shift motor off and manually shifting it into 2h if it doesn't move then your transfer case is messed up and would probably need to be rebuilt or replaced.

 

[Mildew_Inc]

I've tried to manually put it in 2 high and it does the same thing. I've also tried to get it out by backing up. I'll do some more trouble shooting and see what i come up with.

 

[murkinstock]

Alright. Be sure to report back with any findings.

 

[Mildew_Inc]

I went through this recently, and didn't find any information here on doing this, so after working it out on my own, I thought I would post this.

First off: How to check that your locking hubs are working correctly.

1. Put your truck in park. Make sure it is in 2WD high. Set the parking brake.
2. Jack left front wheel off the ground.
3. Find the front driveshaft - it's the round bar (about 1 1/2 inches in diameter) going from the transfer case (behind the transmission) to the front differential (the big round thing in the middle of the front wheels).
4. Turn the front driveshaft. It should turn freely. You should see the half shaft (the shaft connecting the front differential to the wheel) of the raised wheel turn as you turn the driveshaft.
5. Within one or two turns, the hub in the wheel should lock up, and the wheel should start turning, either forwards or backwards (depending on which way you are turning the shaft).
6. Hold onto the driveshaft to try to prevent it from turning. Try to rotate the wheel in the same direction it was just turning. It should turn the driveshaft you are hanging onto as you turn the wheel.
7. Hold onto the driveshaft to prevent it from turning. Rotate the wheel in the opposite direction. You should feel the hub unlock, and the wheel should spin freely without turning the driveshaft.
8. Turn the front driveshaft in the opposite direction you did before. You should see the half shaft (the shaft connecting the front differential to the wheel) of the raised wheel turn as you turn the driveshaft.
9. Within one or two turns, the hub in the wheel should lock up, and the wheel should start turning, the opposite way than it did before.
10. Hold onto the driveshaft to try to prevent it from turning. Try to rotate the wheel in the same direction it was just turning. It should turn the driveshaft you are hanging onto as you turn the wheel.
11. Hold onto the driveshaft to prevent it from turning. Rotate the wheel in the opposite direction. You should feel the hub unlock, and the wheel should spin freely without turning the driveshaft.
12. Lower the wheel, jack up the opposite wheel, and repeat the tests.

If everything happens as described above, your hubs are operating correctly. If not, chances are your hubs are dirty and/or full of grease.

Cleaning your hubs

1. Jack up the front wheel.
2. Remove the lug nuts and the wheel.
3. If the clips on the studs holding the hub in place are still there, remove them.
4. Put a small mark (a sharpie marker works well) on the hub and on one of the studs, so you know which position it goes on.
5. Pull the hub off the spindle. Clean any visible grease out of the hub.
6. Fill the hub up with brake cleaner, and let it sit for 5 minutes. Move the spring mechanism in the hub up and down with a screwdriver several times to move the brake cleaner in and around any grease that may be in it. Dump the brake cleaner out. Repeat several times.
7. Heat up some ATF (automatic transmission fluid) by immersing the plastic bottle in some hot water for a few minutes. Dry off the bottle and fill the hub with ATF. Let the hub sit overnight.
8. Turn the hub over and drain the ATF out. Let it drain for a good 15-20 minutes.
9. Clean all visible grease off the spindle. Put a very thin layer of fresh grease over the spindle.
10. Reinstall the hub (make sure the marks you made on the hub match up with the marks you made on the stud)
11. Reinstall the clips (if any) and wheel.

I was looking at some more threads to try to find out what was going on. I lifted the front driver side and turned the drive shaft and the wheel never locked. And on the passenger side doesn't lock up either. Could the auto hubs be causing the truck not to want to shift up out of 4lo?

 

[MrShorty]

I can't think of how the hubs would have any effect on the transfer case -- especially if they aren't locking.

It sounds to me like the transfer case is getting stuck in neutral on its way from 4L to 4H,except that you say that you have manually shifted the tcase into 2H and it still acts like it is in N. I would begin to suspect something is wrong with the shift fork in the tcase, so that it cannot shift properly.

Another thought -- could the problem be in the transmission? I recall driving an old Toyota pickup that was developing a bad clutch. Because of the gear reduction, you could not feel the clutch slipping in 4L. You only noticed the slipping in 2H/4H because there was no longer any gear reduction to cover up the slipping clutch. It seems like a bit of a long shot, but I could see the same thing happening with an automatic.

 

[Mildew_Inc]

I tried looking up some stuff on the shift fork. Found a little. I was looking for ways to test it. Or is it something I would have to pull the transfercase to get a look at?

 

[FR-425]

It is common for the stop bushing to get crushed or broken which will cause the position switch to get out of wack. Which in turn causes the shift module to loose track of the motor position leaving you stuck in gear. Easily repaired and the only part you will likely need is the plastic(nylon) bushing. get it from your hardware store.

This thread has all you need to know about the shift motor and how to service/rebuild.

http://www.explorerforum.com/forums/showthread.php?p=1102904

 

[Mildew_Inc]

I've tried putting a new shift motor on and have manually tried to change in into 4h and 2h. I put it up on blocks today and was able to get it to go into 2hi. I was able to put in 1 and 2 and reverse worked fine. I sit and let it idle for maybe a min then would not go into gear.

 

[FR-425]

I'm not sure what you are saying.

The truck won't move in 2wd?

Auto trans or manual?

The transmission won't go into gear? or the transfer won't?

 

[Mildew_Inc]

The truck is a manual transmission. With Auto hubs and a auto transfer case. I can not get the truck to work in the high gearing. I can shift from 1st to 5th and reverse works in 4lo. When I try to move it into 4h or 2h it seems to float and not engage right. I have it up on blocks right now. I put manually put it into 4lo. Then manually put it into 4h then 2h. In both 2h and 4h it's will move the wheels for a little while then it will stop working.

 

[Mildew_Inc]

So I finely got back around to working on this thing. I took out the transfer case and sure enough it's the shift fork. I've got the thing out so I wanna rebuild it the transfer case. What all should be replaced. I know I'll need a new pump, shift fork arm and bushings and the rebuild bearing and seal kit. Is there anything I'm missing and was wondering if any one could direct me to some web sites to find the parts.