Help with Vacuum problem

[blackbirdxx]

I was in the process of changing spark plugs on my 97 XLT 4.0 OHV engine (YUCK!) and accidentally snapped a hard plastic vacuum line. The line runs from the intake manifold (right by some red electrical wire) down to some type of round tank on the front passenger side of the vehicle....as far as I can see there are 2 lines that go into this tank...this is the top line.

Now I am noticing that I can't put the truck into 4WD Low...it will go into 4WD OK but when I turn the switch to 4Low, the light doesn't come on....

Are these problems related? I am getting ready to go on a 2100 mile trip this weekend and will be pulling a big U-Haul trailer.....Should I be worried?

Does anyone know what this vacuum line controls?

 

[Robb]

So, did you fix the vacuum line? Or is it still disconnected?

 

[Blee1099]

Originally posted by blackbirdxx
I was in the process of changing spark plugs on my 97 XLT 4.0 OHV engine (YUCK!) and accidentally snapped a hard plastic vacuum line. The line runs from the intake manifold (right by some red electrical wire) down to some type of round tank on the front passenger side of the vehicle....as far as I can see there are 2 lines that go into this tank...this is the top line.

Now I am noticing that I can't put the truck into 4WD Low...it will go into 4WD OK but when I turn the switch to 4Low, the light doesn't come on....

Are these problems related? I am getting ready to go on a 2100 mile trip this weekend and will be pulling a big U-Haul trailer.....Should I be worried?

Does anyone know what this vacuum line controls?

These problems aren't probably related. To shift into 4LO, you have to have it 4HI first and then put it in neutral or Park and turn the knob to 4LO. And that plastic vacuum line that you broke, can it be fixed by placing a vacuum tee on it to re-attach it?

 

[blackbirdxx]

I patched the vacuum line with a rubber line on either end...

As for the 4Low thing, I am in Park when I try to get it to go into low.

What does that vacuum line go to?

 

[Blee1099]

Originally posted by blackbirdxx
I patched the vacuum line with a rubber line on either end...

As for the 4Low thing, I am in Park when I try to get it to go into low.

What does that vacuum line go to?

Try it in neutral, I can't remember if it could be done in park or not but I do know it works in neutral. just shift into 4HI, shift into neutral turn the knob and see if it lights up after you put it back in gear. If it works, you shouldn't be able to go any faster than 35 MPH. On the vacuum line, I don't know which one it is, don't have a picture of it in front of me.