So i have been workin on this vaccuum 4wd i have been fixing all the vaccuum lines on this truc. I have vaccuum down to the switch on the t-case and was not gettin any through it so i replaced the switch with a new one but its still not getting through the switch. I can bypass the switch with a hose and it locks in and out just fine. Is it possable i got a bad switch? Or mabye the hoses are in the wrong place. Does anyone have a diagram where the 4 hoses go?

 

Diagnosing 4WD Engagement Problems on Dodge Ram pickups

 

Here's another good source. Central Axle Disconnect (CAD) System Troubleshooting

 

I have this book marked because soooo many people always need help with this I personally the the posi lock kit which uses a cable Never worry about 4wd not working again!

 

Yeah, so do I. Very handy reference. I like the posi-lock kits also. I don't have one personally (2wd), but have installed more than a few!

 

Are you working on a dodge cummins or your duramax? I don't know anything about the durmax but I just went through this on my dodge. I would say go with a posi-lock kit like daveo- said, but that's in hind sight, oh well, Next time...

 

They also make a kit that keeps the passenger side axle engaged all of the time. Its a lot cheaper, but I believe you see some decrease in mileage

 

I just bought a dodge for a project truck. I still havent been able to figure it out i am gettin vaccume to the tcase switch and it wont go through it to ether two or four wheel drive i have replaced it twice and still not workin. But if i bypass the switch with a tube it works like it should.i have tried pushing the button for the vaccume switch manually and that doesnt even work. Is it possable i got 2 bad switches?

 

Weirder things have happened, I'm sure. Do you know anyone with a similar truck that you know is working? You can try swapping that one in.

 

Ya a friend of mine has a 24v that i was thinking about doing that exact thing with