How do you test them to see if the work, off vehicle? i just had my tranny rebuilt and now I wanna see why my 4 wheel driver didn't work unless i shifted it with a wrench.
Quote from: 84eaglelmz on August 18, 2012, 06:04:16 PM
How do you test them to see if the work, off vehicle? i just had my tranny rebuilt and now I wanna see why my 4 wheel driver didn't work unless i shifted it with a wrench.
There is more than likely a vacuum leak somewhere in your actuator lines or the lines going to the front axle or somewhere going to the 4WD system itself. Do not actuate your 4WD with a wrench if there's obvious signs of no vacuum pressure going to the system(no leak noise when shifting either direction) and if you can't feel the steering change a bit the way it does when you shift into 4WD. If the front axle isn't actuated and the transfer case is in 4WD, you could blow your viscous coupler. Check the entire 4WD vacuum line system for leaks.
The front actuator is working, i pull over the switch to 4wd, to lock the front, then used a wrench to switch the transfer case.
Just get a vacuum pump and try the several nipples. It should move the rod and hold vacuum for a long time. If you get more than 10 minutes of stable vacuum after moving the rod I'd call it good for all practical purposes.
Remember, the two motors are a system. When engaging 4wd first the front switches then the front motor routes vacuum to the transfer case. When disengaging 4wd the rear switches first then sends vacuum to the front. If one is broken then the other may disengage randomly.
when i try the nipples i should plug the other ones right? the air just gets sucked from them.
Not all of them, check the diagram in the Eaglepedia. (http://www.amceaglenest.com/~iowaeagl/guide/index.php?title=Select_Shift)
You have to leave the opposing port on the actuator open for it to move. So the front and back ports on the pie-pan shaped end should not be plugged, but the ones on the stem should be. If the diaphragm is bad it will leak from one of those ports to the other.
The stem seals may be bad... but it would be rare for them to leak so much as to make the system inoperable.