Hi everyone,

Been reading some great material here for any assistance I need to help me overcome this problem with the 4WD.

The story is I have a 4WD, manual tranny all of a sudden, light don't come on and the fronts do not engage. Tried to look for leaks from the ADD but my problem can even be from the solenoids. Let me explain and please do correct me if I am wrong.

I have this unit (I borrowed the pic from off-road.com)


First test, I connect both solenoids directly to the battery. They both "Tick" when powered.
Second test, Engage 4WD, run the voltmeter to both of the plugs, only the "black" on shows 13V but the red one does not. Is that normal?
Third test, turn on engine, check the hose that comes off the manifold and only the red one has air comin out and not the black one. Is that normal?
Fourth test, I do hear the relay engaging "ticking" from inside the dash when I go from 2H to 4H...and vice verca. I am assuming that is ok, Is that a good enough test?

Thank you all for your help...

 

I also measure the resistance on the solenoids and they both show about 40

 

So wife comes over asks me what I am doin, I explained ADD 4WD, 2H 4H, she is like whatever...right? Then she says was it working before the oil change we did on the trip. I said yes and it stopped after the oil change. You sure they did not pull anything unplug, put any hose in the wrong spot? I said, well let me check. Sure enough...the hoses coimng from the manifold were reversed!

She looked at me in disappointment walks back in the house.

So I am good, lights are on, 4WD engaged and am ready for the snow.

 

Glad to see you got it fixed, but you realize you're wife is now an expert on 4wd and will never let you forget it

 

She just got some major unfair advantage there.
....I am sure you'll hear about that one later.

 

threw out the encyclopedia Brittanica the day after our honeymoon.

 

Just wanted to add that my 4wheel drive light wasn't turning on either and the source was a cracked vacuum tube (according to the dealer).

Seems like there are many sources for potential failure when the light doesn't go on.

 

Ok the way the system works is quite simple, when you engage 4WD, there's a switch on the transfer case that switches power to the solenoids in the photo. Vaccum from the engine actuates the coupler system in the front diff. assy, activating another switch to turn on the 4WD light and locks the axle to the carrier. Start the engine and check to see which solenoid is open, then switch to 4WD and check again. if it switched valves then your problem is in the vaccum diaphram at the front diff, if it remained the same check the switch at the transfer case.

 

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LOL! I guess I am not the only one out there with this scenario!

Thanks Bruce for the update. However

Eric the red is right, "Glad to see you got it fixed, but you realize you're wife is now an expert on 4wd and will never let you forget it "

I had to hear abou this over dinner with friends last night.

It seems that all that money I spent on craftsman tools is useless too. Just ask the wifey

 

Does this mean wifey has "hand"?