How to: Manual Control for '95 -'96 Vacuum Disconnect Front Axles

[JDraper]

Well, I finally figured out how to manually control the vacuum disconnect in the '95-96 Explorer front axles!! This modification will allow a Powertrax or other lunchbox locker to be installed in the front axle, and still give you "3 Wheel drive" when you are in 4WD for driving in snow or turning sharp corners.

In the right front corner of the engine compartment, up against the radiator support by the air cleaner, is a connector and the solenoids that control the vacuum disconnect. These are shown below.

How the system works normally:

The main connector for the system is shown on the left of the picture. The two solenoids are in the center of the picture. On the main connector, there are 5 wires. 2 of these are sensor wires (Brown and Black Wires), and the other 3 control the solenoids. The Purple/Orange wire is a constant +12VDC. This is fed to one of the pins on each solenoid. The other two important wires are the Green/Pink wire and the Blue/Yellow wire. When the Green/Pink wire is pulled to ground and the Blue/Yellow wire is floating, the solenoid shifts to unlock the front axle (2WD Mode). When the Blue/Yellow wire is pulled to ground, and the Green/Pink wire is floating, the solenoid shifts to lock the front axle (4WD)mode. All this is automatically accomplished when you rotate the switch on the dash from 2WD to 4WD.


How to manually control the system:

1) Purchase a single pole, double throw switch (SPDT). You can get these at Radio Shack, Newark Electronics. or just about any electronics shop.

2) Connect the center pin of the switch to a good ground and install the switch in a convenient location in the driver's compartment. Add wires to the other two poles that will reach the connector under the hood.

3) Cut the Green/Pink and Blue/Yellow wires in the bundle shown above. Seal off the open wires coming from the harness.

4) Cut the brown wire and tape/shrink tube off both ends. If you don't disable the sensor, the GEM gets confused and won't engage 4wd.


5) Connect the Green/Pink wire to one side of your switch, and the Blue/Yellow wire to the other side.

6) Test the system. Put the truck in park and jack the right front wheel slightly off the ground. Start the motor. Rotate the right front wheel by hand while watching the front driveshaft. If it rotates, the switch is set so that the solenoids have connected the axles. If the axle doesn't rotate, the switch is set so the axles are disconnected. Throw the switch and make sure that it switches mode. LABEL YOUR SWITCH!!

7) Go get a Powertrax locker for your front axle!! The No-Slip part # is 92-0435-2702, and the Lock-Right part # is 2311S2. Your choice on which one to buy, but I'd suggest the Lock-Right because it's more cost effective. Hopefully Gerald Jarrett will be a dealer for them soon!

 

[JoshC]

Nice find Jeff! That will prove to be handy for a lot of people!!

 

[Premier]

Originally posted by JoshC
Nice find Jeff! That will prove to be handy for a lot of people!!

MEMEME

 

[94ZebraRanger]

cool just need to figure how to wire using a relay, shouldn't be a problem.

Thnaks

next is the locker, lockrite front ARB rear.

Tim

 

[JDraper]

No relay needed for this. It's a direct wire because you are only opening and closing the ground. I'd recommend using 16 ga. wire. It's not a high current application because the solenoids are only operating a vacuum orfice, not a mechanical device or light.

 

[GJarrett]

Great writeup Jeff! And yes, I'll be meeting with Powertrax next week, so expect some great pricing for forum members on these lockers within the month

 

[Lifted95X]

Nice Writeup...I plan on using this very soon.

 

[95exploderboy]

Am I to assume that this will also be the cure for those of us who have swaped to he BW 13-54. Instead of keeping our shift motor pluged in?

 

[JDraper]

I don't know what the issues with using the 1354 are, but this allows you to have the xfer case engaged, and still corner without binding or stressing the drivetrain. It allows the right front wheel to freewheel no matter if the xfer case is engaged or not.

The bottom line is this allows you to couple and uncouple the right front wheel from the drivetrain at will.

 

[JoshC]

Originally posted by 95exploderboy
Am I to assume that this will also be the cure for those of us who have swaped to he BW 13-54. Instead of keeping our shift motor pluged in?

Couldn't you run the one piece shaft that the 97's have on the PS. I've got mine in the garage from my axle. I would think you could do this to by pass the vacuum junk.

 

[JDraper]

For those of you following this, please note one small change above. If you don't cut one of the two sensor wires in the wiring harness, the GEM gets confused and won't allow the truck to engage 4WD. Cutting the sensor wire satisfies the GEM and the system works great. I had the truck out in the shale pit up behind my house today, and the mod works as advertised. I then put the truck in 4Auto on the highway with the switch disengaged, and it is very driveable. The only thing out of the ordinary I noticed was that the truck wanted to pull a little in 3WD which was expected.

 

[94ZebraRanger]

Originally posted by JDraper
No relay needed for this. It's a direct wire because you are only opening and closing the ground. I'd recommend using 16 ga. wire. It's not a high current application because the solenoids are only operating a vacuum orfice, not a mechanical device or light.

only reason I want to use a relay not becouse of the current of the curcuit but make it useable with the switches I already have mounted in the dash. All the switches are the same and I want to keep them that way. I will be using these switches till I use them all (total 8) be it lights or?????

Tim

 

[JDraper]

Well, after running around with this and testing it for a few days, I notice that I can still confuse the GEM, causing the 4x4 and 4x4low lights to flash, but the system still works anyways. I've noticed that if I toss the factory switch from 2wd to 4wd before I flip my lockout switch to locked, the GEM gets confused and won't reset the dash lights until the truck is switched off in 2wd mode and re-started. However, even with the dash lights flashing, 2wd, 4wd auto and 4wd low still work.

If I flip my switch to locked before I put the factory switch in 4wd, the GEM is happy, and I can still toggle the lockout on and off without confusing the GEM. Soooo, to keep the GEM from flashing the lights on the dash, and still use 4wd auto on the road, you have to first flip the lockout switch to engaged then put the factory switch to 4wd auto, and then you can disengage the front axle. If you don't care about the flashing lights on the dash (they go out completely after flashing about 10 times), then it doesn't matter how you use the switches.

 

[Lifted95X]

One other question. When in 2wd the CV's still turn and they turn the gears correct? If that is the case, wouldn't you have popping even in 2wd?

 

[JoshC]

As long as your wheels are turning then the CVs are turning. You won't have the popping cause the powertrax doesn't lock in unless it has torque going to it, so it will unlock around corners.

 

[Lifted95X]

Yes, but he installed the lockright so I figure that would be pretty nasty driving that, even in 2WD.

 

[JDraper]

In 2WD, you don't even notice the lock right being there. No popping, no thumping...nothing. Just like driving an open diff. That's where the '95's and '96's have the advantage over the newer trucks, the vacuum disconnect uncouples the passenger's side front wheel from the drivetrain, so it doesn't matter if the powertrax locks up or not, it won't affect the way the truck drives.

 

[Lifted95X]

Ok..so even in 2wd then you switch it to unlocked?

 

[JDraper]

Yep. In 2WD you leave it unlocked. However, if you forget to unlock it in 2wd, it will still drive fine because there is no power being applied to the front axle. The powertrax locks when power is applied. When no power is applied, it acts like an open diff. You will get some clicking when you corner with it engaged, but it won't affect driveablility.

 

[Lifted95X]

I still am a little confused.