So I have an 89 dokota sport, and the 4x4 was working fine, all winter, but then it got stuck in 4wd, and I finally got it to shift back into 2wd and now it wont shift at all.

I went into the faq and tried to test the vacuum of the CAD system, and the test is to see if the vacuum shifts from one line to the other, but I didnt have any vacuum at all to either line. I felt with my fingers, and then took a thin piece of paper (a receipt I had laying around) and got nothing, I tried to look through the line to see if there were any holes, kinks, or anything else blocking it, I sprayed them liberally with wd40 and still nothing,

What could cause no vacuum? does this mean I have a bad transfer case?

any help is very appreciated, I really tried to fix this without posted a thread, but I have hit a wall.

Thanks in advance!
-Koenig

 

There is a switch on your transfer case that switches the vacuum. There will be four lines going to it. Two will be under vacuum (one goes direct to the engine, the other goes to the vacuum reservoir on the cross member then back to the engine) and the other two lines go to the front CAD. Ensure you have vacuum to two of the lines, and that you can blow air through the two that go to the front. I would replace all those lines if I were you. The switch is like $10 too so worth replacing if it is suspect.