well everything else on the truck I bought checked out, but I didn't even check the 4 wheel drive system. When I pull the lever nothing happens, and the light does not come on. any ideas, any more info needed.

 

Vaccum actuator is probably

the culprit... www.4x4posi-lok.com that should solve your problem. The vaccum actuator is prone to failure due to the lines not giving vaccum or recieving it due to being all plugged up with oil and so forth. It might just be a loose line from the transfer case, there is a plug on top of it, kinda tricky to get too, but that could be it, also check the lines that run to the little motor the yellow is supposed to suck in air, and the red is supposed to push air out... 90 percent of the time it is what it is, a new actuator i think is about 90 bucks that 4x4 manual kit is about 200, 206 shipped in two day to your door.. mine just came in.. guess what im doin this weekend...

Pm vssman, he is wicked when it comes to 4x4 systems, i learned alot from him, also type in four wheel drive in your search, and catch up on some readin.. thank you!

Tx

 

thanks TxDiesel007 you've been quite helpful, and answered all my questions even before I got the truck.

 

Is the 4X4 not engaging or is it just the light not coming on? The 4X4 switch and/or wiring to the switch often fails even though the 4X4 is still working.

It's easier to check that first.

 

I would take a look at the vacuum lines, if you need to just blow them out with some compressed air (all ends disconnected of course). This should take care of the problem. Then when you put it back together use some silicone and zip ties to get the system 100% sealed. I had some issues during a snow storm once, it ended up being moisture in the lines. The moisture caused the vacuum switch to freeze in one position, so replaced that for around 25 bucks, then the new rubber block that connects to the switch wouldn't seal so had to buy new lines for about 35 bucks. If I had time I could have just pulled the switch out of the T case and soaked it in some solvent to clean it out but when the snow is flyin' there is no time.

Now, I have no experience with the posi lok, and I was one click away from ordering one except it was brought to my attention that the factory system lasted 160K, and plenty of plowing and is a 100% sealed unit. The posi lok is a cable that can stretch a bit and most importantly, you don't use 4x4 too often and they after it sits in the salt and wet, the day you do need it it may be froze. I just don't like the idea of the cable, and also the way they stress the last 1/4" of engagement - it makes me feel like the last bit of engagement can be stubborn at times. The other benefit is 2LO, so it is a toss up. I have not regretted my decision to stay with the oem style, though.

Good Luck!!!

 

Matt..

id take a look at what i just posted not more than three minutes ago... There is no stress in engaging it. Yes the cable might stretch, BUT it has a nut on the outside, and you can farther thread the housing into the thread if it actually stretches..... If you decide to go that way you wont be disappointed.. But from you, i have learned alot about vacuum lines and my Old OEM system. I have nothing against it, it just let me down when i did really need it...

The switch not working? Mine did after removing the plug, cleaning it out, and puttin it back in again.. not two weeks later i got stuck... and my OEM failed. I tired blowing the lines, and new vaccum lines, i replaced just about everything but the steel lines, and vaccum actuator.. i like mechanical stuff, but then again, this is just MHO...

Tx

 

I learned about the CAD the hard way... Mine wouldn't engage immediately but seeing that it happened to be winter and cold, it worked good enough for me. Well, after a few too many delayed engages my transfer case decided to break the snap ring. Although I can't prove it, both I and the rebuilder thinks the shock of the front axle engaging caused the snap ring to stress and finally break. So why did the CAD take a dump??? Well, I found oil in the lines. Apparently even though I had the truck serviced for the vacuum pump check valve recall, it was not installed - go figure. The oil caused the diaphram in the motor to leak along with all of the unions between the rubber hoses and steel lines. It doesn't take much to loose the vacuum "pull" to engage the CAD. With that I had a couple of options: 1) replace the CAD and lines, 2) Posi-lok, 3) Dynatrack hubs, or 4) swap a Ford axle with lockout hubs. Guess what's cheapest and provides 100% engagement? Yup, Posi-lok. I personally use mine just like if I had manual hubs - pull the cable while I'm stopped or slightly rolling. No BANG or clunk anymore like to stock system. The cable is wrapped in a plastic cover so water instrusion shouldn't be too bad. (The company that makes them is from Michigan I think so they know salt rust). Anyway if it's a concern, spray the cable with penetrating fluid at every oil change - that's what I used to do when I was a mechanic 20 years ago on the parking brake cables.

Just my $0.02