My 4wd won't engage. I think it's a vacuum issue.

rickyd123rickyd123 Member Posts: 3
edited November 2024 in GMC
I have a vacuum reservoir under the hood. The line that feeds it is unhooked, and I can't figure out where it's supposed to be plugged into vacuum at. I replaced the vacuum actuator on my 4wd, but it doesn't collapse from vacuum when the 4wd is engaged like it should.



Comments

  • rickyd123rickyd123 Member Posts: 3
    My vehicle is a 1995 Gmc Jimmy 4.2L auto. I forgot to put that in my ppost.
  • thecardoc3thecardoc3 Member Posts: 5,828
    With the engine idling you should be able to hear a vacuum leak. If someone disconnected this on purpose, they might have capped off the nipple. Any manifold vacuum source will be fine if you cannot find the original connection point.
  • rickyd123rickyd123 Member Posts: 3
    I had to take it to a mechanic. The hose goes at the back of the intake. You can't see it. you have to feel for it. Once the vacuum hose was connected my 4wd worked fine.
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