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In some places the hard plastic tubing is not continuous, but the pieces are connected by a soft rubber hose over the ends of the pipe. Sometimes the rubber gets old and porous and simply falls off.
If you have that problem in one place you can safely assume that the other places will soon follow..
In some places the hard plastic tubing is not continuous, but the pieces are connected by a soft rubber hose over the ends of the pipe. Sometimes the rubber gets old and porous and simply falls off.
If you have that problem in one place you can safely assume that the other places will soon follow..
Then the AWD should be the vac lines on the transfer case vac switch to the front axle CAD - check if you lose vacuum when selecting 4WD ( simply select vent to feet, put it into 4WD and if vent goes to defrost you have a leak in the 4WD apply state only)
Got under my 5.9 today to try to fix that vacuum leak or whatever the issue may be. So I followed the lines from the actuator to the t-case, blew into the line, red was good but the black one sounded like there's a leak somewhere.
From the actuator to the lines that sit in front of the t-case (metal lines) was good but the black pvc line, from in front of the t-case to the top of it, still sounded like it had a leak somewhere, so I took it apart from the t-case, blew in one end while keeping the other end closed with me thumb. Didn't notice and hissing sounds. I applied some contact cement on the ends that go into a rubber boot just in case there was a lose in pressure where I couldn't see and put the line back together and blew in it again. Same thing happened, so I put it all back together. 4WD still isn't working and there's still a little smoke. when I turn the wheels 15-20 degrees left or right, the truck won't move under its own power and when I press the accelerator to give it power, it will start to move, then will rock a little as if I'm pumping the brakes also when im turning while in motion.
Hopefully this all makes sense. If not, I hope I can better explain with questions you have.
OK, a little info about the 4x4 system.
The vacuum operated central axle disconnect is "helping you to save fuel while in 4x2 by reducing the number of parts that are moving"
There is a sliding collar on the front axle that either connects or disconnects the inner half to/from the outer half of the shaft. This is a vacuum thingy, pulling the diaphragm in either direction by applying vacuum on one side and opening the other side to atmosphere. This is done by the valve on top of the transfer case.
So, air going through one hose and not through the other is normal, and the hoses must change when you select 4WD.
Simple trick to test is with the truck running unplug red and black from the CAD and check which side has vacuum when in 2wd and when in 4wd.
No vacuum - search for either no vac to the valve o valve completely gummed up., lose connector..
No change in vacuum - valve defective or not installed properly.
Both 2WD and 4WD vac lines seemed to be working ok. 4L engages but still does that weird rocking thing that I explained earlier.The diagram helped and I replaced the connector to the vac pump because it was rotted and cracked but didn't make a difference in anything. ill keep diving in and updating. I appreciate the help everyone.
Does it go into 4 low or just into low without 4WD?
If the CAD is stuck it will not engage and you will have 2WD only. The 4wd light is activated by a switch in the CAD, so if you have 4wd but no light it might be in the wiring.
But your rocking with the wheel turned sounds very much like you were in 4WD.. Sounds like too much for the limited slip acting up, this would make your rear axle hop.
Both 2WD and 4WD vac lines seemed to be working ok. 4L engages but still does that weird rocking thing that I explained earlier.The diagram helped and I replaced the connector to the vac pump because it was rotted and cracked but didn't make a difference in anything. ill keep diving in and updating. I appreciate the help everyone.
I believe it goes into 4L because I feel it engage but it still hops. When I turn the wheel.
Get under the truck while engine off, 2H selected- try to rotate front propshaft by hand- must spin freely. If not, either 4WD engaged in transfer case or CAD engaged or both.
Lift the right front wheel with the parking brake applied and the truck off and in 2H - try to rotate the wheel. (Should rotate easily), then start engine in park and check again- should still rotate easily- shift to 4h, wheel should not move more than a part rotation anymore, recheck with 4L.
As for your description it seems to me that you might be stuck in 4WD, or also might not have 4WD and an additional problem with the limited slip diff.
06-23-2019, 01:47 AM
