OK. Here is where I am at.
Got the truck into 4 low and nothing. Has been this way for awhile now. I could tell when I got stuck in a snowy parking lot (about 1/3in acc) (uphill of course). With this Cummins torque and crappy tires its not fun being in Northeast Ohio right now. Anyways.

I put the truck on a jack, got the front right tire up and it spins when I have it in 4 low. Its not supposed to....correct?
Found a vacuum line that may be loose Or just not completely together. (found) Got those 4 that go down to the area where the lever engages the 4x4. i have white and green lines that go to the back of the motor then up to the vacuum stuff right above the valve cover. Hopefully this all makes sense. OK. The white line is attached up there but the green line is not... Is this my problem? The other 3 lines are going places hooking to things. Whether or not they are cracked, i couldnt tell from just glancing at them.

Any diagrams or help would be amazing. I had a Hayes manual but cant seem to find it... you know now that i need one.

Thanks guys/gals

 

ill check mine, but im 80 percent sure all lines should be connected

 

thank you good sir. just got back in from the garage with my brother and we are stuck at this point. but willing to bet that line has something to do with it

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also just to give all the info i can. When the white line goes to the vacuum lines above there is a spot beside it for another line (for the green poss?) but it had some sort of nipple covering on it instead of just being open. So im not sure if it was done intentionally or if it actually is right and nothing is wrong with the green line. The green line also has an end peace that looks funny where it ends. It ends just behind the valve cover behind the engine. If i need to ill try to find my battery for my camera and add pictures of whats going on. Ill do my best to get that done tomorrow or tonight. Or even Sunday. Depends on when i have time.

 

anybody got somethin? or a diagram i can look at. Not finding anything...

 

Does everything seem to work OK in 4-high? If so, it would just about have to be a vacuum problem. There is a vacuum switch inside the transfer case that, when 4-hi or 4-low is selected, activates the Central Axle Disconnect (CAD) located in the right "long side" front axle tube. This CAD uses a vacuum actuator to slide a collar over the splines of the two-piece axle shaft to "lock in" the front axle.

In general, the CAD is a POS as the actuator is easily damaged/jammed and ANY vacuum leak in the system can render it useless.

I'd look at the switch inside the t-case first. Start the truck and pull the vacuum line going from the engine vacuum pump to the t-case and and confirm there is vacuum going to the switch. If so, replace that line and engage 4-hi. Pull the line going from the T-case to the CAD. Check for vacuum at the t-case switch outlet first. If present, check at the end of the line at the CAD. If everything checks out, repeat in 4-low.

 

i feel your pain, these trucks dont go anywhere in 2wd! they need lockers! too much torque, weight and no flex

 

yea it is very frustrating.

update. Check it in 4 hi and low. got the front end up and still rotating in neutral. Still waiting to see if those vacuum lines (or line) was suppose to be off like that. I cant find my Haynes manual so im stuck as of right now. If i could find out/ or see a diagram for those vacuum lines i could check that. Then by process of elimination start narrowing it down to getting into the transfer case to see if that "button" isnt being hit right by the actual lever.
hey DUKEBOY.. did you find out how those vacuum lines went right there behind the valve cover?! Let me know if you took a look and there was no gap in what would be the green line coming from the transfer case... for some reason mine for whatever reason looks like it has been capped or is off. Not sure if its suppose to be that way. I would get pictures but cant find my flippin battery to the camera.... (im losing everything, i moved 3 times in the last 4 months!!!)