Extra wire from transfer case

[lil_Blue_Ford]

The transfer case is the one that came in the truck back in Jan of 1998 when I bought it with 14 miles on it. Now at 368K, it's been falling apart. LOL
I use to live further out of town on a gravel road that was very steep, so I was always shifting from 2 to 4 high so as to minimize potholes in the gravel. Never had problems then, but that was back in the 2010s. Now I hardly think to put it in 4 wheel drive.
Couldn't tell in the video, do you remember if your connector was 'full' of all 8 wires? Thinking now that I need to look at the new plug on the motor and see if all 8 wires are 'filled in'. If so, I'll try splicing the 'extra wire' in the new motor's plug into the one from the transfer case. Sound logical?

Interesting.

Yes, the 2000 transfer cases that I had which didn’t have the extra wire from the t-case only had 7 wires in the plug and a blank spot. Dad’s 99 had the extra wire and it filled that last spot. Which is why I asked if your truck had 7 or 8 wires on the truck side, if it had 8, then that’s likely where the missing wire goes. If it has 7, then adding a wire to the plug won’t change a thing because there’s nowhere on the truck side to connect. If that makes sense.

But the wire colors on the new motor don't match the original, as far as positions go. And the original plug on mine only had 7 wires installed. So there was one 'blank' in the plug, and the extra wire was the 8th. Was thinking maybe they integrated it into the plug on other years, since your description of the wires don't match my plug. What do you think?

The wire colors changed randomly on the shift motor side. Depended on who made it and when. They can be traced out but should come pre-assembled into the correct position.

 

[lil_Blue_Ford]

Only if it's the same color. Some plugs had more than 8 wires. I would suspect that if it's an 8-wire plug, you will not find anything extra.

2 wires for motor
2 wires for sensor
4 wires for position switches
= 8 wires. There won't be any unused.

On the 99 and the 00 Rangers I’ve worked with there is two heavy gauge wires for the shift motor and 5 for the contact plate. The 99 was the only one with an 8th wire, and that went into the t-case under the rear output. All three were pinned exactly the same other than that 8th wire.

 

[Effieman]

Interesting.

Yes, the 2000 transfer cases that I had which didn’t have the extra wire from the t-case only had 7 wires in the plug and a blank spot. Dad’s 99 had the extra wire and it filled that last spot. Which is why I asked if your truck had 7 or 8 wires on the truck side, if it had 8, then that’s likely where the missing wire goes. If it has 7, then adding a wire to the plug won’t change a thing because there’s nowhere on the truck side to connect. If that makes sense.


The wire colors changed randomly on the shift motor side. Depended on who made it and when. They can be traced out but should come pre-assembled into the correct position.

The extra wire on my case connected to a separate wire that also came out of the motor, so there was a total of 8 wires connected, 7 in the connector, and one with the spade connector. I'm figuring IF the new motor has 8 wires in the connector, then the 8th wire would be for the extra wire that comes from the case, which would seem to be what you explained. Does that make sense?

 

[Curious Hound]

Only if it's the same color. Some plugs had more than 8 wires. I would suspect that if it's an 8-wire plug, you will not find anything extra.

2 wires for motor
2 wires for sensor
4 wires for position switches
= 8 wires. There won't be any unused.

First off, please forgive me. I made some mistakes here. It should read 5 wires for position switches. So, 7 wires installed is normal and expected on the newer trucks with full-time live axles. The speed sensor and clutch are not needed. The older trucks needed 10 wires due to the speed sensor and clutch. There may have been variations over the years. We also know that Ford uses up inventory during model transitions. An early live axle truck could very easily end up with a t-case containing a clutch right from the factory. There is no reason for a third wire from the motor and it especially would not connect to the clutch. The clutch signal would come from the controller in the cab. The motor only needs 2 wires - 1 positive, 1 negative. The controller swaps them to change direction.


The main point is, your truck doesn't seem to need the clutch. So you can ignore that wire. Let it dangle in the wind and move on with life.

 

[Effieman]

First off, please forgive me. I made some mistakes here. It should read 5 wires for position switches. So, 7 wires installed is normal and expected on the newer trucks with full-time live axles. The speed sensor and clutch are not needed. The older trucks needed 10 wires due to the speed sensor and clutch. There may have been variations over the years. We also know that Ford uses up inventory during model transitions. An early live axle truck could very easily end up with a t-case containing a clutch right from the factory. There is no reason for a third wire from the motor and it especially would not connect to the clutch. The clutch signal would come from the controller in the cab. The motor only needs 2 wires - 1 positive, 1 negative. The controller swaps them to change direction.


The main point is, your truck doesn't seem to need the clutch. So you can ignore that wire. Let it dangle in the wind and move on with life.

You mentioned before that the clutch was for slow speeds. Do you know what slow speed would be?
I'm now thinking I should maybe just try to shift on the fly to 4 high at maybe 10 mph and see if I get the grinding noise again. If it sounds good, then I won't worry about the wire.... Since, of course, I have to be stopped with the clutch in and brake on to get into 4 low.

I know the build date on my truck was December of '97. Do you happen to know the cut off year of the live axle?
This seems to be getting complicated. LOL

 

[Curious Hound]

This thread has gotten confusing with people talking about 2000 and newer systems. Let's review and confirm some things. I just looked back and see that we're talking about a '98 and you just confirmed a build date of Dec 97. I believe this actually puts you in the era of the PVH hubs. Not full-time live axles. They are automatic vacuum operated hubs. So, think back to hearing the grinding noise. Are you SURE it came from the transfer case? The PVH hubs are notoriously unreliable and you may have had a hub not fully engaging for one of your front wheels.

One more note. Do not use 4x4 hi or lo on hard surfaces.

To answer your question about shift - on - the- fly speed, see photo below. It mentions being able to do it up to 55mph. I normally stay less than about 35mph, personally.

 

[Effieman]

This thread has gotten confusing with people talking about 2000 and newer systems. Let's review and confirm some things. I just looked back and see that we're talking about a '98 and you just confirmed a build date of Dec 97. I believe this actually puts you in the era of the PVH hubs. Not full-time live axles. They are automatic vacuum operated hubs. So, think back to hearing the grinding noise. Are you SURE it came from the transfer case? The PVH hubs are notoriously unreliable and you may have had a hub not fully engaging for one of your front wheels.

One more note. Do not use 4x4 hi or lo on hard surfaces.

To answer your question about shift - on - the- fly speed, see photo below. It mentions being able to do it up to 55mph. I normally stay less than about 35mph, personally.
View attachment 143966

Yes, I have the vacuum hubs. The noise seemed to be coming from the transfer case. And since the truck wouldn't move at all, even the back wheels weren't 'engaged'. I don't think I've ever shifted from 2 to 4 at over 40 mph. I have used 4 high on hard surface (regular road), but only for very short distances (1 or 2 blocks) and only going straight as to not get the shudder (for lack of a better word) when turning in 4X4.

 

[Effieman]

Now I'm really confused. I crawled back under the truck last night and found that the original truck side plug has 8 wires going to it. Yet the original shift motor, and the replacement only have 7 wires in the connector.
I'm going to have to go find some gravel or mud and see if the 4 wheel drive is working correctly or not before I worry about this any more.
Thanks for all the info, ideas, etc.

 

[lil_Blue_Ford]

Now I'm really confused. I crawled back under the truck last night and found that the original truck side plug has 8 wires going to it. Yet the original shift motor, and the replacement only have 7 wires in the connector.
I'm going to have to go find some gravel or mud and see if the 4 wheel drive is working correctly or not before I worry about this any more.
Thanks for all the info, ideas, etc.

Yeah, @Curious Hound makes sense, a PVH hub vs live axle thing. I’m trying to do a million things at once and it didn’t click for me. The 2000 trucks I have are all live axle, the 99 is PVH.

Sounds like you need to connect the wire, it should go to the 8th wire on the truck harness. I’ve already grabbed some 8-pin plugs with a bit of wire out of junkyard trucks that were tore apart to get replacement plugs and pigtails for situations like this. Those 8-pin plugs all use the same pins, just the color of the plug determines what plus it will connect to. All you need is an 8 pin rubber end plug and a wire. Those plugs were used all over Rangers/Explorers/Bronco2/full-size trucks.

 

[pjtoledo]

I'm feelin' a bit rascally, so let's add to the confusion.
adding my now worthless 2 cents worth of comments.

shift on the fly, version unknown.

normal 2wd operation while in motion:
vacuum hubs are disconnected, so axles are not rotating (and other stuff)
transfer case in 2wd, so front drive parts are not moving either.

shift on the fly is selected (while in motion) but moving parts don't like stationary parts.
4wd controller engages the transfer case clutch which brings the front output parts up to speed to match the rear.
then the controller engages the front hubs.

so, while moving, if the clutch ain't clutchin' the wheel hubs will be crunchin'
well no, probably not,,,
if the controller doesn't see that the tcase front parts are up to speed it won't/shouldn't activate the hubs.

by the way, as the tcase shifts from hi to low there is a small position where neither is engaged,
that puts the entire tcase in neutral. as in it can roll away if in park or in gear.

in my opinion that blue spade connector does not look like a factory connector.
can anybody verify that wires connector type?

does the 8th spot in the connector go to 12 volts when 4wd is selected?????
if you apply power to the brown wire does the front driveshaft lock up? (is the clutch working?)
you might want to put an ohm meter on that wire first, if it's a dead short don't apply power.


corrections? comments? suggestions? obscenities?

 

[pjtoledo]

Now I'm really confused. I crawled back under the truck last night and found that the original truck side plug has 8 wires going to it. Yet the original shift motor, and the replacement only have 7 wires in the connector.
I'm going to have to go find some gravel or mud and see if the 4 wheel drive is working correctly or not before I worry about this any more.
Thanks for all the info, ideas, etc.

just jack up a front tire. it should lock up if 4wd engages. there will be considerable drive line slop/play but the
wheel definitely should not rotate.

 

[Effieman]

I'm feelin' a bit rascally, so let's add to the confusion.
adding my now worthless 2 cents worth of comments.

shift on the fly, version unknown.

normal 2wd operation while in motion:
vacuum hubs are disconnected, so axles are not rotating (and other stuff)
transfer case in 2wd, so front drive parts are not moving either.

shift on the fly is selected (while in motion) but moving parts don't like stationary parts.
4wd controller engages the transfer case clutch which brings the front output parts up to speed to match the rear.
then the controller engages the front hubs.

so, while moving, if the clutch ain't clutchin' the wheel hubs will be crunchin'
well no, probably not,,,
if the controller doesn't see that the tcase front parts are up to speed it won't/shouldn't activate the hubs.

by the way, as the tcase shifts from hi to low there is a small position where neither is engaged,
that puts the entire tcase in neutral. as in it can roll away if in park or in gear.

in my opinion that blue spade connector does not look like a factory connector.
can anybody verify that wires connector type?

does the 8th spot in the connector go to 12 volts when 4wd is selected?????
if you apply power to the brown wire does the front driveshaft lock up? (is the clutch working?)
you might want to put an ohm meter on that wire first, if it's a dead short don't apply power.


corrections? comments? suggestions? obscenities?

Yeah, I'm thinking maybe just connect a ohm meter to the 8th spot in the connector, checking for both resistance and voltage in each shift position, then doing the same on the wire from the transfer case itself, like you suggested. And I was thinking of lifting the whole truck on jack stands and try it out that way, but your way would be easier.
It also makes me remember years ago I shifted into 4X4 on the fly in snow, yet I still seemed to be sliding. When I stopped and stuck my head out the window, I noticed that when I started moving, only the rear wheels were spinning, yet the light on the dash said I was in 4X4. Went back and fourth from 2 to 4 high several times and then it finally was working. Didn't have the problem again for years.

 

[Effieman]

Yeah, @Curious Hound makes sense, a PVH hub vs live axle thing. I’m trying to do a million things at once and it didn’t click for me. The 2000 trucks I have are all live axle, the 99 is PVH.

Sounds like you need to connect the wire, it should go to the 8th wire on the truck harness. I’ve already grabbed some 8-pin plugs with a bit of wire out of junkyard trucks that were tore apart to get replacement plugs and pigtails for situations like this. Those 8-pin plugs all use the same pins, just the color of the plug determines what plus it will connect to. All you need is an 8 pin rubber end plug and a wire. Those plugs were used all over Rangers/Explorers/Bronco2/full-size trucks.

Maybe I'll go back to Pick N Pull for a connector, then if I need the wire, I can easily splice it in since it would have the right pin.

 

[Curious Hound]

so, while moving, if the clutch ain't clutchin' the wheel hubs will be crunchin'
well no, probably not,,,

You're on the right track. You just put the crunch in the wring place. It was the gears in the t-case crunching while trying to mesh. That has to happen before anything in the front axle happens.

in my opinion that blue spade connector does not look like a factory connector.
can anybody verify that wires connector type?

It goes in the 8th position on tje connector he has. Don't know who put the spade connector on it.

All the rest of the wiring in that connector belongs to the motor. So, if you replace the motor, you jave to cut that wire because it doesn't unplug from the t-case. That's why mine has a butt splice in it.

you might want to put an ohm meter on that wire first, if it's a dead short don't apply power.

It won't be shorted. The clutch wire will read the resistance of the coil. The wire it connects to in the plug will read voltage when the controller tries to shift from 2wd to 4-hi.

It all makes sense now.

 

[Effieman]

It won't be shorted. The clutch wire will read the resistance of the coil. The wire it connects to in the plug will read voltage when the controller tries to shift from 2wd to 4-hi.

It all makes sense now.

Will the wire in the plug only have voltage while shifting on the fly, or could I test it here while parked?
Any idea how long it should have power (constant, 2 seconds, etc)?