BW4406 controls like 98-02 Expedition/Navigator

[CDW6212R]

Hello, has anyone done any research into the electronic control of the 98-01 Expedition/Navigator 4WD system? I have so far learned that those trucks had four position switches, 2WD, A4WD, 4WD High, and 4WD Low.

I need to find a compatible BW4406 transfer case for those trucks, to use in my 98 Mountaineer. I could do the "brown wire mod" to obtain a 2WD for my truck, but using the four position switch etc. would be better, if the control can be done.

Did anyone look into those control systems from the Expedition or Navigator? I wouldn't mind if the three identical selections could be wired to match the Explorer system. The fourth 2WD selection could be wired to perform the "brown wire mod" function.

There is very little to find with a Yahoo search for the electronic operation of those trucks. The countless useless reviews and ads waste time in search engines. Thanks for any help,

 

[gijoecam]

I sent you an e-mail response to your e-mail... could you copy and paste it here for me? I didn't save a copy...

Thanks!

 

[Brans Freestyle]

i would say get the switch and then find a way to wire it to do the brown fire mod like you said above... it couldn't be TOO hard

 

[gijoecam]

The switch alone isn't going to do a thing for you... the switch just has four different resistances. The GEM ultimately determines how to handle the input voltage. Short of a GEM transplant, it's not going to work.

 

[CDW6212R]

Here's what Joe sent me today;
"
Here's what I can tell you about your inquiry. The super-short version is that it won't happen without some SERIOUS computer circuitry. If you know an Electrical Engineer familiar with control system theory, it's time to call in all your favors and then some if you want to make it work.

Now, that being said, here's what I know from perusing the schematics. The system out of the Expeditions/Navigators was basically a combination of the system used in the Explorers with the system used on the F-150s. The front driveline used a super-sized system similar to the F-150. It utilized a center-axle disconnect on the front axle to break the passenger side axle shaft when in 2wd, similar to the 95 and 96 model Explorers. In theory, this allowed the front driveshaft and front diff carrier to remain stationary in the 2wd setting.

The selectable 44-06 case in the Expedition functioned essentially identical to the 44-05 in the Explorers. It's an electronically controlled on-demand system that utilized the ball-ramp clutch mechanism. When set to the auto mode, it varies the duty cycle of that clutch to maintain traction. When set to 4high or 4low, the system locked the transfer case in at 100% duty cycle, thereby linking the front and rear driveshafts. Low range, of course, involved shifting the low range planetary gear set into play as well.

The bad news is that the 4-position switch used in the Expeditions was not the only difference. The system relied on the GEM to control the Torque On Demand relay just like all the second-gens, as well as the center-axle disconnect on the front axle. The hybrid combination means that there will be no plug-and-play on the system you're aiming for. The switch has four different resistances instead of the Explorer's three, and it's the GEM that ultimately determines how to control the system.

Now, if I was going to do it to my vehicle, I'd first have to pour over the schematics for a few days and make notes on ALL the differences in the wiring between the GEM and t-case for an Expedition and the GEM and t-case for an Explorer. Then, I'd yank the front axle from a 95 or 96 Explorer along with all the associated vacuum plumbing for the center axle disconnect and install it all in the Explorer/Mounty in question. Then, I'd install the 44-06 t-case and GEM in the Mounty, and french the wiring for the CAD, t-case, and TOD relay into the GEM from the Expedition. It would also involve feeding the signals from the GEM and t-case into the rest of the integrated systems: PCM, ABS, SRS, etc. No small task to say the least.

Plan B: Stick with the 44-05 (assuming that's what you have to start with) and do the brown wire mod. If you've already got the AWD 44-06, ditch it for the manual 13-54 out of an F-150 and be done with it. You'll spend a lifetime trying to get an electronic setup to integrate nicely into the rest of the system.

Good luck, and let me know if I can help any more.

-Joe"

Thanks for those details. More specifically Joe, what would the Explorer 4405 GEM do with the odd fourth(2WD) signal from the Expedition switch? Regards,

 

[MountaineerGreen]

Have you checked V8 boat builders thread?- he did a TOD conversion with a 4406.

http://www.explorerforum.com/forums/showthread.php?t=97181

 

[CDW6212R]

Yes Evan, he is the only other I know of who did the electronic version. He used all of the BW4405 Explorer parts. It does work for those three switch selections because the internal shift motor functions and BW4406 are the same as the BW4405. I was hoping to take advantage of the 2WD Expedition switch position to obtain 2WD(without a separate switch - brown wire, relay).

 

[MountaineerGreen]

Ahh, I see. You are far braver than I am, I wouldn't want to tackle that wiring mess.

 

[CDW6212R]

Well the idea of using a different vehicle GEM module is the last thing I would want to do. I doubt that the functions are all alike. Unless someone could verify the massive number of wires to all match, I'll be using the V6 4WD GEM module like my 99 has. Regards,

 

[gijoecam]

Via e-mail, bringing it back to the boards...

Joe, you may have confused what I have and was planning. I've got a 98 302 AWD Mountaineer, and the first plan is to use the V6 4WD Explorer GEM, TOD, 4WD relay, and the TC harness. That is what Aaron did with his 97 302 Explorer, with a 98 Expedition BW4406.

So we know that the 4WD Explorer GEM will work with the 302's, the only difference is the 4WD functions inside. There are only two GEM modules for 95-01 Explorers, 2WD/AWD, and 4WD.

So you think that the BW4405 GEM module would not recognize all three of the same switch selections, A4WD, 4WDH, 4WDL? And who knows what it would do with the 2WD resistance. If the switch could work I would jump at it, alter the 2WD signal if needed to trip a relay etc. Thanks for your input, it is good to try to work this stuff out before buying odd parts that aren't so easy to find. Regards,

I wasn't aware that the GEM from the V-6 would play nice with the PCM from the V-8s. I never followed Aaron's thread (was busy planning a wedding at the time IIRC)... might be time to get caught up with it.



Functionally the t-case out of the Expedition works the same as the 44-05 from the Explorer. The difference is in the way the GEM handles the fourth position on the switch, and the fact that that generation of Expedition has the CAD on the front axle. The switch uses the same wire to feed the signal back to the GEM regardless of which position it's in. The difference is in the resistances in the switch and, therefore, the signal voltage at the GEM. Even if they switch uses four, the GEM is only programmed to interpret three ranges. If you wanted the fourth to work, you would need the GEM from the Expedition, which again, would likely be a much bigger pain than it's worth.



Also, we're overlooking one important aspect of how the system works: In order to have a true two wheel drive system, you want to completely disconnect the front driveshaft from the front wheels, which is why they used the CAD on the trucks. The transfer cases are not designed in such a way that they will support extended periods of large differences in driveshaft speeds (e.g. tire-roasting burnouts). Excessive burnouts can and do cause internal damage to the t-case unless the front driveshaft can be disconnected from the front driveline (hence the need for the CAD). If that is your intent, you will need to use the CAD front axle out of a 95 or 96 Explorer. If you can live with three simple positions, (auto, 4high, 4low) you can always include the brown wire mod, but that will, of course, require an extra switch, and again, it's not condusive to wheel-roasting burnouts.



-Joe

 

[wchain]

I just sold a 99 A4WD Navi, and 99+ trucks do not have a seperate 2WD switch, A4WD, 4Hi and 4Low. I bought the truck stuck in 4Hi, and ended up changing th transfer case fluid over and over again. After the 5th change, the A4WD was working properly. Great design concept, but due to lack of maintenance by the previous owner, the trucks driveline was in poor shape.

 

[CDW6212R]

Thanks Joe, I'll accept that the big truck GEM is the only way to utilize the four position switch. My intent is to run the truck in A4WD almost always, and on road. The mileage may go up a hair, that's part of it. But I may want to hit a dyno a couple of times. Being able to make it 2WD more easily with the same switch was my wish, I like OE type appearances etc. Regards,

 

[gijoecam]

You still have the option of doing the brown wire mod to it to give yourself a true 2wd, but that won't allow you to run it on a dyno. I'd still remove the front driveshaft for that... It's only a few bolts and you eliminate any chance of damage.

Also, there are no significant mileage gains to be had by making it 2wd anyways. Short of using the CAD, the front drivetrain is still rotating all the time, so you're not really saving anything significant. It saves a bit of wear and tear on the front ring, pinion, and driveshaft joints, but that's about it.

-Joe

 

[Turdle]

Here's my theory--
I think Don has gotten himself addicted to solder flux smoke while doing the wiring on his half and half, and he's worried he'll run our of wiring mods--

 

[CDW6212R]

We'll see, welding creates a good haze too.