4x4 trouble

[Detainabull]

Hey guys how's everything? I'm having a little bit of 4x4 trouble and can't quite figure it out. Nothing is engaging. Not 4Hi or 4Lo. The lights all come on and when I lift the front wheels up I can spin the tire which in return spins the front shaft and the main drive shaft.
My father in law gave me this explorer with 290k on the odometer and has never used four wheel drive. Does this sound like it could just be the front hubs not engaging?

 

[Detainabull]

Ok so a quick update. I jacked up the explorer on all 4 corners. Threw it into 4hi and at idle nothing. Only the rear tires spin. Step on the gas an hit approx 25mph and the front wheels take off. Repeat this process for 4Lo and it is the same.

The front tires should take off just like the rear tires correct? Even at an idle they should be rolling? Any help is appreciated. Thanks

 

[justgetinstarte]

Sounds to me like the t-case chain or something more down stream is slipping.

 

[TechGuru]

There are no hub locks. They're standard CV joints like a FWD car.

Soiunds like a bad clutch in the transfer case? Sounds like maybe it got towed wrong and it got destroyed...any repo records on CarFax?

 

[Detainabull]

I never thought about a clutch. That seems possible as when I put it back on the ground it never wants to engage almost like being under load is preventing it.

Worth replacing the front transfer case? I'll just pull one from a yard considering this is a free vehicle. Or worth digging into the internals on this one?

 

[TechGuru]

Front transfer case? There is only one transfer case and it is in the middle bolted to the rear of the transmission. You can get a freshly remanufactured transfer case for just under $1000 at RockAuto.

There are a few things I would check before replacing it.

1. Is the fluid full and of the correct type. Transfer case uses regular Mercon unlike the transmission which uses Mercon V (very different fluids, don't ever mix them up!)

2. Be sure full power is getting to the clutch by checking the voltage going to it. I'll let someone else explain how, it's a brown wire...

3. Spinning in the air is one thing, that don't mean enough power is getting to them to actually help the vehicle, the only way to really test it is to remove the rear drive shaft (be damn sure your parking brake is in good working order!) and try driving it in 4x4 HI with the rear drive shaft removed.

If you're not sure it might be worth it to spend $125 ish on a diagnostic fee at a Ford dealer to find out what the problem is for sure before buying any major parts.

 

[Detainabull]

I'll play with it a little more and see what I can figure out. Its a new system to me but imma big DIYer so digging into things isn't really a problem. I'll double check a few things and see what we have going on. Thanks guys

 

[Detainabull]

Quick update, pulled transfer case and opened it up. Everything looks great. No broken teeth, nothing loose, even the clutch pack looks very good with no wear. Anyone have any tips on checking the voltage going to the clutch? The helical cam is in good working order and the hi lo collar is moving properly but it seems the clutch pack itself could be the issue?

 

[Detainabull]

And after reading some more, does the coil have to be engaged for the lights to illuminate on the dash? Or can the transfer case engage properly if the coil does not have 12V to it? I'm going to put the TC back into the vehicle and start troubleshooting again but needed some clarity in the chain of events causing the lights to indicate in the dash

 

[TechGuru]

Sheesh, I would have tried driving it with the rear driveshaft removed long before removing the transfer case.

See if this helps:

I believe the light will come on regardless if the clutch is working or not. I see no feedback loop to verify the clutch is working.

 

[Detainabull]

Well at some point I did try w just the rear tires on jack stands and no progress w that test either, I will however leave the Driveshaft out this time around lol. Thanks for the diagram!

 

[TechGuru]

Well at some point I did try w just the rear tires on jack stands and no progress w that test either, I will however leave the Driveshaft out this time around lol. Thanks for the diagram!

It should have pushed the jacks over and drove...

 

[Detainabull]

It def did not push em over or even move forwards. Case is sealed up now and ready to put back in in the morning if time permits. I'll keep you guys posted

 

[Detainabull]

So the transfer case is back in, left the rear driveshaft out. Engages to 4wd and tires start rolling IF they are in the air with no load. Put the explorer back on the ground and it just revs when trying to drive w no rear driveshaft. Makes the slightest bump and that's all. Put a meter on the brown wire for the magnet and only 2 volts at most in both 4 hi and 4 lo.
I took a wire straight from the battery and supplied it w 12 volts, took another reading in 4 hi and 4 lo. The voltage read out right at 13, left the wire tied in to keep the voltage, put it in Drive and NOTHING.
Is it possible the electromagnet itself in the case is bad? Anyone have any other ideas to look at?

 

[TechGuru]

Sounds like a bad tow killed it or maybe someone running two different tire sizes. Bad thing is I don't know were to get a new clutch by itself, I'm not seeing them at RockAuto.

 

[Detainabull]

There's a transfer case laying out at the local LKQ. I'm half tempted to just go get it since it's out of the vehicle. Someone took the trans and left the TC laying under it. Or Even just take the clutch and everything else on the shaft instead of the whole case

 

[TechGuru]

Actually after looking at the schmattic, I see both + and - of the clutch go to the 4x4 control module and not just + with the - going to ground so to do a proper test you need to disconnect both the brown and the dark green from the 4x4 and apply both + and - directly.

I'm not sure about the polarity or if it even matters....

 

[Detainabull]

Ok I'll do that tonight or first thing in the morning and post the results. Thanks for the help

 

[Detainabull]

Just checked the voltage again and it's at 14 volts when 4wd is engaged and in Drive. Looks like I'll tear it back open and change the clutch components

 

[Detainabull]

So I took the coil, clutch, and clutch pack out of a used transfer case and swapped it into mine. Put it back in while leaving the rear driveshaft out and the truck pulled right off. Not sure what piece being replaced actually fixed it. I have a feeling it was the coil though, putting a meter on it while out of the case it read out zero ohms. Something tells me it should read something but hell im no electrician. But the four wheel drive works to say the least! Thanks for everyone's help on this