4405 Tcase Takes Time to Decide to Engage, then Doesn't Let Go.

[GJarrett]

Yep, it's a 911! problem since I've got a front locker and it is staying engaged on hard pavement.... I did a search, got a gazillion hits, and couldn't find an answer. This is really strange.

When I engage 4wd, the tcase may or may not decide to engage for a minute or so, or maybe until I get up to a higher speed. Then once engaged, it will not turn off: the magnetic clutch stays locked. The 4wd lights do not start flashing and it doesn't show an error. Here's the strange thing.... I have the "Brown Wire Mod" and can turn off the switch (which should physically turn off power to the tcase clutch) and it still stays engaged even when no power via the brown wire is keeping the magnetic clutch turned on! At first I thought that I fried my switch but it's okay, and I have removed it and left the brown wire unconnected where I cut into it, so that confirms that the tcase stays engaged even when the brown wire is cut.

It gets stranger..... I can turn off my engine and restart and it is still engaged even with no power through the brown wire and after the engine had been turned off! The ONLY way for me to get it to let go is to unplug the wiring harness with all of the wires going into the side of the tcase (and then of course I get the flashing 4wd lights ) to remove all input into the tcase. Then if I replug it in again, reconnect the brown wire, and later on try to use 4wd, it will once again decide when it wants to engage - maybe right then, maybe sometime soon, maybe a little later on - and then once engaged it will again refuse to let go and stay engaged until I crawl under the vehicle and unplug the wiring harness.

What is going on? Bad GEM or TOD relay? How is it staying engaged even when the brown wire is not sending it power, even after turning the engine off?

 

[Trckmagik]

I have no clue about that TCase. Maybe its time for a Atlas II

 

[Blee1099]

I had something similar happen to me last February at Rausch Creek.. It would decide not to stay in 4 HI. I replaced the hall sensor and a few other things plus cleaned the xfer case connector.. Hopefully your transfer case isn't going up Garrett. If it is, you should thinking about doing a manual xfer case.

 

[Jefe]

Its about time you toasted the 4405.

I'm guessing its a physical problem with the case seeing as it stays locked without power. Would also explain the lack of 4x4 lights. But it doesn't explain why it goes to normal when you unplug the case harness.
I assume you spiced the brown wire mod switch in between the GEM/4x4 relays and the t-case, so the only way the clutch could still be getting power is if the harness is shorted somewhere after that. You taken a volt meter to the brown wire and ground going into the case to make sure you're truely not sending 12V in?

 

[GJarrett]

I've got four weekends to:
1) fix this,
2) replace ball joints,
3)diagnose and fix an overheating problem,
4) just bought a fixerupper house that is currently uninhabitable but I have to move in it in May,
5) plan a wedding and honeymoon,
6) on a cross country trip to Utah, Colorado, and Texas.

I have zero spare time right now.

I don't have the time or money to do any swaps. My tcase works, this is some electrical short or problem in the GEM or TOD relay or something. I just need to replace something and plug it in. Atlases and manual swaps will have to come later, no way I can pull something like that off before Moab.

 

[GJarrett]

Jefe, I haven't done that yet, I may go buy a cheapo VOM at Radio Shack and try to get readings, that would help the diagnosis. Thanks.

 

[Blee1099]

I've got four weekends to:
1) fix this,
2) replace ball joints,
3)diagnose and fix an overheating problem,
4) just bought a fixerupper house that is currently uninhabitable but I have to move in it in May,
5) plan a wedding and honeymoon,
6) on a cross country trip to Utah, Colorado, and Texas.

I have zero spare time right now.

I don't have the time or money to do any swaps. My tcase works, this is some electrical short or problem in the GEM or TOD relay or something. I just need to replace something and plug it in. Atlases and manual swaps will have to come later, no way I can pull something like that off before Moab.

I say your a lil busy definately. Just get a pair of pliers and manually turn the transfer case.

 

[Jefe]

I say your a lil busy definately. Just get a pair of pliers and manually turn the transfer case.

Um. . that doesn't work with the 4405
yes, you could go from High to Low doing that, but the case needs power to engage the front clutch.
Worst case gerald is you just live with the flashing 4x4 lights while onroad right? Unplug for street driving and then just wait for it to engage on the trail (or does it take longer than that to engage?) (heck I'm still living with them )

 

[Robert]

Gerald,

My only four thoughts are the ones you already mentioned (TOD relay and GEM), shorting wire and internal transfer case problem. Since the clutch releases when you disconnect the TC harness, that to me at least partially eliminates the TOD relay. At first I was thinking that the relay is getting fused closed which would prevent it from opening back up once the power is removed, but when you unplugged the harness, the power is removed from the relay which allows it to open. The GEM is a definate possibility since I have seen many issues related to it (although none quite like this). If you know of another '99 owner (might work with other years but you would have to look in to that) locally that would let you swap temporarily, you could either confirm or eliminate it. Next guess would be a wire that is shorting out with the TOD wire (brown wire) between the break for your switch and the transfer case. If another wire is shorting out on your brown wire. Once you remove all power from the system by disconnecting the connector, it lets it release. You can verify this by measuring for current between the brown wire and ground when it locks up and doesn't release. If you see current there, then either the brown wire is shorted somewhere, your relay is staying closed or your GEM is screwed up and supplying power to it when it shouldn't. If you measure current there, I would then remove the TOD relay and look for voltage at the coil side of the relay. If there is voltage present, then something is causing the TOD relay to activate when it shouldn't (GEM or short). If there isn't any voltage at the coil then the relay is staying closed and not releasing (bad relay). After all of this if you still can't make any progress, then something inside the transfer case is likely bad.

 

[GJarrett]

Yeah a short would make some sort of sense. Since it also has the problem that I cannot make it engage when I first apply 4wd and have to wait to let it decide to, maybe there's a short jiggling back and forth under the vibration of my vehicle movement (?) That wouldn't explain it staying locked in once it does engage though, an intermittent short should jiggle back apart sooner or later....

Saturday I'm replacing balljoints; I'll also buy a VOM and test some voltages and try to narrow this down some. I'll report back then and see if one of us can figure this out. The fact that it can stay engaged even with the brown wire disconnected really has me scratching my head.

Thanks guys!

 

[JDraper]

I'd guess the same as Robert on the short circuit somewhere. That seems to be the most logical issue. It would also explain the random engagement. I did have a similar issue with my neighbor's Expedition. It locked itself in 4wd lo and wouldn't come out for the life of it. We ended up taking off the shift motor and manually putting it in hi, and then it was fine and went back to 2wd like it was supposed to....until we tried 4wd lo again. At first it wouldn't go in, then it dropped in and wouldn't come back out without removing the motor again and turning the shaft by hand. We took the motor apart and cleaned it, but that didn't help. Turned out to be a bad hall sensor on the tcase motor that was working intermittently (Just like Ben's). We replaced the motor and sensor, and the problem has gone away.


Good luck with all your projects!!!

 

[dogfriend]

My understanding of the Transfer Case Clutch is that it will only engage when power is applied to the coil. The mechanical design of the engagement mechanism is supposed to insure that the clutch disengages whenever the current is cutoff. With that in mind, there seem to be two distinct possibilities:

1. You are somehow getting current on the brown wire leading into the transfer case, even though you believe that the power should be off. Unfortunately, I don't think this is very likely but it should be easy to verify with a DVM the next time the T-case is stuck on.

2. There is a mechanical issue with the transfer case which is preventing the clutch from engaging/ disengaging. Unfortunately, I think this is more likely based upon your first post. I think that somehow the mechanism is binding.

I don't have the schematic in front of me, but if you were somehow getting power to the brown wire with the key off, then you should test the TOD relay to see if it is still suppyling power to the brown wire. The TOD is a solid state relay - it is possible that it is passing current with no signal from the GEM - therefore engaging the clutch. I would hope for that.

 

[Vozar]

Dang that sucks GJarrett. Thats why im doing the 1354 swap so i dont have to deal with all the 4405 crap. Hope u can still make it to Windrock. Good Luck! Keep us updated!

Matt

 

[Opera House]

There is a sticker on the outside of the transfer case, WARNING SHOCK HAZARD DO NOT OPEN. When you open the case there is another sticker on the inside, WE SAID YOU WOULD BE SHOCKED.

There isn't much inside a 4405 case. The shift motor only decides only if the planetary gear reduction is used. Though, on a bad day it could put you into neutral. The electric clutch puts power to the front wheels only when power is applied. This clutch is not like the A/C clutch that engages a clutch plate. This is an eddy current clutch that puts drag on a spinning plate. That drag makes three little balls climb a ramp and put pressure on the clutch plates. One common problem with these is the rear housing that mounts the rear shaft bearing wears. Test your rear flange for up down play with transmission in neutral. This can cause excessive wear on the clutch engagement mech. A few people have had problems with this ball/ramp mech. I'd say put away the voltmeters and get out the wrenches.

These aren't hard to get apart and do an inspection. Gasket is just silicone. Be carefull with shift rod. It is very easy to snap the guide pin. Rebuild kits I've found don't include clutch parts.

 

[GJarrett]

Aaaargh!

I was on the way to get a multimeter this morning.....

but the d@m# tcase is working perfectly today!

 

[dman726749]

as my dad (an electrician) would say, it sounds like the fm theory f'in magic.

 

[general x]

make sure you fix it right!!! My dad told me "If you leave it it will die at the most innapropriate time". The pos cable to my starter selonoid wont make contact cuz its corroded so it only somtimes works. It cault me off guard one day when i needed to get to work fast. Its still broke, Ill fix it....Tommorrow

 

[GJarrett]

But I won't know what to fix until it decides to go bad again so I can test and diagnose the problem.....

 

[dogfriend]

Since you have the brown wire mod, you could put the truck up on jack stands, put the truck in gear and cycle the switch to try to induce the problem. The transfer case clutch should engage when you are sending power on the brown wire because it will see that the rear wheels are moving faster than the fronts and will kick in the 4wd to try to match front and rear driveshaft speeds. When you turn the switch off, it should disengage the clutch even though the GEM will be trying to match driveshaft speeds. If it sticks, you will be able to do your voltmeter tests.

BTW, I agree 100% with OperaHouse.

 

[GJarrett]

Found It!

Firstly, thanks for all of the help and attention guys. It ended up being an intermittent short that was my fault and part of the switch installation.

I installed my brown wire mod switch in my drivers door, which meant I had to route wiring to the switch up through the kick panel and going into my door. I did not open up the protective covering that surrounds all of the other wires going into my door and install my switch wires into the existing harness, but rather simply left the switch wires standing alone and apart from the others. Over time and many door opening/closings, I have managed to pinch those wires enough to finally bare one that has managed to short against the metal of the door. Today it finally broke apart completely.

So, it wasn't a tcase problem or anything the fault of Ford, but my own wiring technique when I did the brown wire mod.

I'll do a fantastically professional wiring installation this weekend

Once again, thanks for the help. It took me less than fifteen minutes to find the exact location of the problem, once I got the meter readings last night and noted that they changed depending on whether my door was open or shut. Thank goodness it was a simple problem and easy fix