4x4 doesn't work

[Waynesrage54]

Went out in my 95 dodge 5.9l 4x4 and went to engage it in 4x4 light came on once,then it went out. The front drive shaft was turning but no light and no front tire spin. What might be the problem here?

 

[dapepper9]

Check your vacuum lines to the front axle

 

[joepizuro]

Also actuator could he stuck. Turn wheels and drive forward and back

 

[Yeret]

Check your vacuum lines to the front axle

This. I have the same issue going on. There are two vacuum lines going to the actuator on the front axle, a red one and a black one. In 2wd, one line should be pulling vacuum while the other should not. When you shift into 4wd, the signals should swap; the line that was pulling vacuum should now do nothing while the line that was doing nothing should be pulling vacuum.

In my case, I have the proper vacuum in 2wd however when I shift into 4wd, neither line pulls vacuum. I've read that a faulty vacuum switch, which is mounted onto the transfer case, can cause this. Unfortunately, when I tried to remove it to replace it, I couldn't get the damn thing to budge. I tried to find a write-up to see if I was missing something, but have so far found absolutely nothing. Guess everyone just swaps in a mechanical switch when they start having issues with their 4wd, LOL.

Let us know how things turn out. It would certainly help me.

 

[Waynesrage54]

I took into our automotive shop at the school to test. It was barely getting vaccum in 4x4 so we swapped a new line in for it and it still didnt produce very much. Today while i was driving down the road the 4wd light came on, and took it back in the shop at school and the front tires were turning, so i think now one of the lines are backwards since it kicked in in 2wd. Thanks for the replies and advice

P.S. My shop teacher told me about that mechanical 4x4 to get rid of the vaccum actuator