I have recently dont a upper intake gasket and had to remove vacum lines to move the intake out of the way. i know there is 3 hoses that connect to the intake on the very top are for the 4WD and they are connected but its wont go into 4x4 just 2H and 2L. I checked the lines everything is hooked up good! but it doesnt engage. the hoses that connect to the intake at the top.. is there so kinda of order? all three holes pull vacum so i cant really pick and choose.. one hose has a filter looking thing, one is a regular line, and the thrid has another hose connecting to it. Is there some kind of order or do they just go on anyway! also before the intake gasket the 4WD worked fine! could this be electric? the vacum hoses connect to what looks like electric hook ups?

Thanks for your time and help!

 

i have a leaking front axel seal also.. would low fluid have something to do with this in anyway?

 

no one has any idea?

 

well i dont know what i did but its working now i unpluged the connector on the axel then repluged it and it work :-/

 

Try switching the two vacuum lines that are ON the ADD Actuator (near the front diff.). If you happen to have the vacuum lines reversed AT the VSV on the passenger side inner fender, this should force the ADD to lock (engine running).

I don't think a leaking seal should cause the ADD not to engage. It's possible that the actuator diaphragm that causes the ADD to engage is leaking.

Look here for more info:
http://personal.utulsa.edu/~nathan-b...26addcontr.pdf

Mike in AR

 

I wrote this up when I had a "no 4wd lockup" problem:
https://www.yotatech.com/forums/f16/diagnosing-no-4wd-lock-up-58634/

The end result was something else, but I did walk through some diagnostic steps.

Basically, you need vaccum, and there are a pair of electrical solenoids that route the vacuum to either side of the diaphragm. You should be able to hear the solenoids click when you click the button on & off. Pulling the lines at the diaphragm should net you vacuum when the button is pushed or released.

With the lines on, you should be able to hear/feel the accuator sliding in the diff. If it's hard to hear, a screwdriver makes a great stethoscope! Put the metal side screwdriver on the diff, then the handle in your ear.



edit:
Ahhh.. sounds like it was electrical. n/m!