So I have a vacuum issue and no 4x4 while looking for vacuum leaks I found this.Can anybody tell me what are the hooks up to?It comes off of the vacuum pump. Thank you


It's almost like a check valve or a junction

 

Coming up off the vacuum pump, that is more'n likely your vacuum source. Has to go somewhere..... start lookin' around for another line that just 'ends'.

 

Does your heater only blow on the windshield?

There are only a few things running off that vacuum line. One end goes to the pump. On the 12 valves, there's a cruise control servo under the driver's side battery that needs vacuum, there is a vacuum line that goes down to the transfer case (on 4wd) and then up to the CAD, and the HVAC system.

 

OK so here is all of what I have going on & nothing figured out so I'll start fresh.When I bought the truck I noticed this green vacuum hose was unhooked also so was the electrical connection to the exhaust brake. I do not believe there is an exhaust brake on this truck. I see nothing in the exhaust which is an aftermarket 6 inch, well I had air coming out of the front vents. put in a new transfer case and now No air out of anywhere but the defrost& the four wheel drive does not work.
I found this vacuum hose disconnected and if I run it to the Green Line... Which please if you know what this green line is for let me know anyways... I get four wheel drive but in a two wheel drive position meaning the linkage is in 2 high
& it only goes into 4 wheel drive in one of the positions though the 4 wheel drive light comes on in all positions but one. But still air only out of the defrost. I bought a posi lok to lock the 4 wheel drive in manually but I know vacuum leaks can cause excessive blow by so I want to fix the vacuum leak. I found the line with the disc is supposed to connect to the T fitting that is going to the exhaust brake. so I don't know if I should remove the exhaust brake and put it back to how it was originally because there still has to be something this was hooked too.And this braided line coming off the back of the terminal goes to a brown vacuum line it's actually kind of the squares line with black heat shrink around it what is this for? Sorry for the poor grammar I usually use speech to text but today its really bad I cannot use my right arm long story. any thoughts help ideas would be greatly appreciated.I do body work for a living and I was shocked yesterday that a fellow called me and wants me to come see his 2007 I believe 4 door long bed 4 wheel drive with the 6.7 he wants to give it to me for some work. But that doesn't mean I want to toss this truck aside.Ive Pub plans for a 2nd gen Cummins sense I learnt about them after I bought my 95 gas burner& I I have no plans to abandon this truck so please if you can help I would appreciate it plus I might change his mind or want to make some kind of crazy deal lol Thank you








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is the green line runnin into the pressure switch for the 4x4? it will be on the side of the tcase. normally on drivers side. it will be right where the tranny shift linkage is. normally there is 4 lines that run into it. 2 of which goto your CAD on the front axle. if you are gettin 4x4 in 2hi instead of 4hi, it sounds like the 2 lines on the CAD is backwards just swap them the other way. thats all i can really think of.

 

I found some old pix from when I first bought the truck a few months ago.The green line was unhooked &the vacuum on pass side of solenoid was unhooked & the line that was plugged into it from the T was indeed where the loose VACUUM I had went, hooked up now I have vents still no 4x4.So Now here's what I don't get I have no 4x4 but if I go try to move past the neutral on the t case it'll grind, so why no 4x4 if the neutral engages don't it need same thing? Aldo when I did hook vacuum up to that green hose that's when I got 4x4 in 2 hi so now I'm thinking something goes to that. If I can't find it I'm hooking up the posi lok today.

 

personally i would do the posi-lok and forget it. the posi-lok is way better guaranteed to work everytime and it gives you the 2-low option. and just a thought i always put tranny in neutral when i wanna goto low on the t-case.

hookup the posi-lok
make sure the tcase can go into 2hi-4hi-and 4-low and actually gives you the hi and low ranges... would suck to only have hi range. if your only gettin one range then i would be lookin at the lines going to the pressure switch.

 

What's that goofy solenoid doing in there?

Clearly something is amuck. There should be a vacuum line coming off the vacuum pump, going up to a T that has one lead coming back to the cruise control servo, and then one goes across the dash to feed the xfer case and the HVAC.

The xfer case has 4 lines, a vacuum source, a vent, and two that go up to the front axle CAD that switch to either pull or push the actuator.

The 4wd indicator switch is driven by the CAD.

If the indicator light is on in all shifter positions except one, I would wager the vacuum hoses at the CAD should be reversed (or reversed at the xfer case).

The actual shifting of the xfer case is totally independent of the indicator light and the CAD actuation. Verify that your xfer case shifter linkage is adjusted properly. In 2wd mode, you should be able to grab the front driveshaft and spin it with your hand (engine off, in park). Same with N, but make sure your parking brake works. Don't drive over yourself. When you shift it into 4wd, you shouldn't be able to spin the front shaft. With the engine running, you should still be able to spin the front driveshaft in 2wd and N. If the CAD's vacuum lines are swapped, the 4wd indicator would be on and you shouldn't be able to spin the front shaft in 2wd.

I would probably remove the solenoid and simplify the vacuum system, put it back to stock. Or remove it from the xfer case (cap the lines off) and put a posi-lok in and then just have the vacuum pump feeding HVAC and cruise only.


Oh, and as far as shifting goes, are you putting your trans in N to do the shift, going 3-5 mph for low range?