Problem Solved. Don't Know How.

[McSlug]

After hearing a mystery noise whilst driving, getting a misfire code and having some performance issues. I started this thread.
http://www.explorerforum.com/forums/showthread.php?p=2466370
The issue remains a mystery even though I have fixed it. I'll explain as follows and hopefully someone can explain to me.
First of all
In my defense as to mistaking a vacuum issue for a stuck in 4wd issue. I took my father for a drive. As he has an uncanny knack for diagnosing any type of car issue. He told me it sounded like a constant misfire and it may have a cracked head or (unconvincingly) it could be a vacuum leak. But there was evidence that disproved constant misfire and other theories. In any case we where mystified and I stuck with vacuum leak as it can cause who knows what, when and where?
As far as not knowing it was in 4wd this is where it gets tricky. I get binding as soon as I turn the wheels on any hard surface when in 4wd. This did not occur and It did not handle any different.

After giving up on the vacuum leak. I played with the 4wd selector switch. I select 4hi, no noise. I select 4lo, grate,crunch,clang 4lo selected. Back to 4hi, click 4hi selected. Back to auto, no noise. Light on dash corresponds to selector switch position.
I pull shift motor. Now the letters I was expecting to see (from pics posted here) was 4L 2H 4H but I had was L N H. I assumed N was 2wd and selected this manually. Fired up the engine, put it in drive, car doesn't move, I rev a bit more, nothing. Go to put it into park, get grinding noise, hmmmm weird. Turn off engine. Deselect N put into H , go to put shift motor back on temporarily, out of alignment. Move selector switch to 4hi, motor fits, bolt it back up, start engine, select auto, drive off, no noise, pedal @ WOT , pedestrians shake their head at hoon flying down the road.
It now drives faultless and shifts from auto to 4hi but I don't quite know what I've really done and what the problem was. I can only think selector shaft was in a "almost there" position causing the noise. I realize I may have realigned my shift motor and it will probably go out if I select 4lo unless I fix it. But WTF is up with the N position and no drive line engagement?

Any clues as to what the issue was would be great.

 

[Electrohacker]

H = high
N = neutral
L = low

there are probably 2 detents in the H range for 2 and 4 wheel

 

[McSlug]

mine looked exactly like this except no numbers and an N where the 2H is.
http://www.explorerforum.com/data/500/27133Tcase02.JPG

I did think of N being neutral but lack of another mark made me think it was the 2wd position.

 

[hworksinc]

It sounds like you had it sitting just between 4-Low and 4-High when it wasn't moving anywhere (when you had it in "N"). This is mechanical neutral, and will not supply power to any output shaft.

As an aside, there is no mechanical 2WD on these transfer cases. 4WD is enabled by engaging an electric clutch that engages the front output of the transfer case (that is the lone wire that goes into the transfer case). All the shift motor does is switch between high and low. (So with the clutch engaged you can get 4-High and 4-Low depending on the shift motor position; with the clutch off you can have 2-High or 2-Low - with the "brown wire mod" you can manually control power to the clutch).

It sounds like your shift motor may not have been fully seating in the 4-High position. I have no idea why that would happen, or what it would actually do, but I could see it making some noise since the gears wouldn't be fully engaged.

 

[McSlug]

After my test drive yesterday, I tested shifting from auto to 4hi and back. It seemed to work so I just parked it up for the night satisfied my problem was gone.
Today it's back, so I guess my theory of not going into 4lo also pertains to 4hi.
So I will remove shift motor and post a pic of selector shaft position. Then try to realign and not touch selector until I get time to rebuild the shift motor.

 

[hworksinc]

After my test drive yesterday, I tested shifting from auto to 4hi and back.

Shifting from Auto to 4-Hi doesn't have anything to do with the shift motor. All that does is energize the electromagnetic clutch. Auto 4WD simply energizes the clutch on-demand when the system detects wheel spin - no mechanical "shifting" is involved. The only time the shift motor is activated is when switching from 4-Hi to 4-Lo (and from 4-Lo to 4-Hi).

I can't think of a way that engaging the clutch would cause the problem to come back (if the problem is related to the shift motor), unless engaging the clutch just jostled things enough to bring the noise back (e.g. possibly made the shift motor hop a bit out of position).

BTW, when's the last time the t-case fluid was changed?

EDIT: I was just looking through your other thread, and saw the part about being stuck in 4WD. The only way that can happen is if the electromagnetic clutch is getting power when it shouldn't, or is rubbing for some reason. If there's a lot of crud between the clutch and it's mating surface, it could cause noise from the clutch when it's not engaged, and I suppose could even transfer some power to the front wheels. It's a bit of a stretch, but technically possible. As for the power issue, the control system could be activating the clutch inappropriately, or there could be a short in the power line for the clutch. You should get a meter and check for voltage at the clutch wire. With the vehicle on and parked with 4WD in "Auto" you should see 0 volts on the line. Flip the switch to 4-Hi and you should see 12 volts on the line. As an aside, it is normal to not hear anything when switching from Auto to 4-Hi, since there is no mechanical movement in the T-case (the only thing happening is the clutch engaging, which it almost silent).

 

[McSlug]

I don't know about the fluids. I bought it bout a year ago as a second car for trips to my beach shack and a bit of fishing. Didn't plan on driving it as much as I do. I plan to do all the fluids very soon. I've done the timing chains, OOM12, and put new tyres all round, trans fluid was next.

What's with the 2H in the pic then.http://www.explorerforum.com/data/500/27133Tcase02.JPG

 

[hworksinc]

I think the 1st gen Explorers had a mechanical shift from 2WD to 4WD - so that may be from a 1st gen truck (or perhaps that pic was from a different vehicle that used the same series transfer case). There should be a few threads around here on it - I think one of the "brown wire mod" threads has a good discussion of the workings of the 2nd gen transfer case.

 

[McSlug]

Hworksinc: Thanks for your help/info. Yes you are right it is an older t-case and shift motor.
This issue is really doing my head in.
I seemed to have cleared it but it came back when I turned the selector switch from auto to 4wd. The noise does not seem to be coming from the t-case itself but it is only there when I engage the drive line. I still have the bogging down issue, it's like the drive line cant keep up with the revs so it chokes. but this was gone for a short while as well as the noise.
I have bought a stethoscope. In the morning I will try to see if I can isolate where the noise is coming from. I hate working under cars on stands let alone while they are running and in gear.
My father and my (mature aged apprentice H/D mechanic) cousin are coming to help me on the weekend. I was going to do the uni joints soon (6months ago) so I may do them and pull the T-case at the same time. I may be barking up the wrong tree but I'll do it for the fun of it. Even if it's to eliminate it.
I read the 44-05 rebuild diary last night, several times, I recon I can have it out ,check it out and put back in, in about 6 beers. Between now and then I will keep hunting as well as doing fluid change in trans and t-case first thing.

 

[McSlug]

Sloppy Transfer Case

OK. Cut a long story short. I found myself at "Transmissions R Us" (local trans repairer) buying a filter for the transmission.
Well as I started to tell him of my woes he gave me that look, you know the one you get when they know what your problem is straight off the bat, but they just smile and nod and politely wait for you to finish your story, well that's the one I got.
It turns out I have ovaling of the bores for the shift fork rod. Which is confirmed by this thread that I read back to front a few times last night.
http://www.explorerforum.com/forums/showthread.php?t=182071
(Glacier991 is a Legend) any one with the 4405 should read this (it's quite common).The casings for these need to be re-machined and sleeved in the fork rod bore's and the output bearing shaft.

I might add, it was great to see a trans tech that's not full of BS.

I still have no mechanical explanation of what exactly is creating the noise or what else in the drive line or trans is effected.
For now I have corrected my issue.(no noise and no bogging down) Next I have to come up with a plan of attack and do some math. (this is not a cheap fix) Machining alone looks like it's gonna cost more than my timing chain job. Then there's parts.