hey guys new to the forum.

Ive owned this car for a about 7 years now and it used to be on edwards afb as a security vehicle ran on natural gas, weird gov't stuff.

Anyway the 4wd was unhooked and the vacuum thing under the battery when we got it and took forever to figure out that thing was unhooked, hooked it up worked fine for years after. My brother ended up driving it for few years and bought a new truck, so the old chevy sat. Im driving it back up to washington from socal on I5 so 4wd not a big issue if it doesnt work.

Whats happening is ill shift it into 4hi nothing happens(floor shifter) so im assuming because it sat for a few months it has lost vacuum pressure. Worked fine before that. How do I fix this? anyway i can just blow some air in there with a compressor?

My brothers ranger did the same thing and a local shop just lightly fiddled with it and it was fine. Wondering if i can do the same or what other routes i can take.

Sorry for the long story -Luke

 

Sounds like a bad vacuum switch on the transfer case or vacuum leak from broken lines..

 

I'd start with the vacuum lines under the hood. Those are the ones that seem to dry rot first. I assume the '93s were similar to the 2nd gens, so the vacuum line from the engine should go to a one-way check valve, and then split three ways - one line to a vacuum reservoir, one line to the transfer case vacuum switch, and one line into the cab for HVAC controls.

The only foolproof way I've found to diagnose vacuum leaks is to get a MityVac and apply vacuum to those three lines (and for the vacuum line to the t-case vacuum switch, doing so with the truck in both 2WD and 4WD). You'll also want to see if the vacuum reservoir has any transfer case fluid in it, which is common when the t-case vacuum switch fails (read more here).

Other things to check -

• One-way valve under the hood.
• Make sure the lines at the t-case vacuum switch are making a good seal around the switch.
• HVAC vent controls - usually a high correlation between lack of control of air flow, and 4WD problems.

Hope that helps - good luck!

 

so i found some broken vacuum lines right next to the distributor, fixed those.

But the front dif still wont engage so either theres more leaks or the vacuum switch has failed?

 

problem solved. lifted the front end and pushed some air through it with a mighty vac tool, front dif poped right in.