Hey guys, first poster. I have been creeping for the past few days, and before you jump on me, I promise I have done the searches and read countless threads on here about this issue. I just could really use some advice from anyone who might have tackled this. Also, if this isnt in the right area, Moderators, please feel free to move it!

OK, so I have an 04 5.4 4wd supercrew.. All of a sudden at certain speeds, or goin up inclines, I hear the grinding of what I know know to be my actuator on my driver side. Its not all the time, just when the truck is under a load. It stops as soon as I let off the accelerator. I tried going to 4HI at a lower speed when this was happening, and it stopped the issue. This let me know that I had an issue with the 4wd.. I started off by trying to keep it easy, checked the check valves first. One was allowing air both ways!! Score! problem solved right? Ran to the store and picked one up, and replaced it.. went for a drive.. same issue.. dang.. Ok, so seeing how I dont have access to a pump tester, I know it sounds ghetto, but tried testing some by blowing, and sucking (no dirty minds please).. Everything appeared to be ok, the best I can tell by that. SO I dove in headfirst to the actuator.. I got it off (finally.. freaking upper arm wouldnt let go), and pulled it out... I blew into the valve and it appeared to working properly... I started the engine, and hooked and unhooked the hose to it, and watched it work like it was supposed too... After all of that, I went back to hoses, and was checking the basic ones around the cllanoid sp? (which is the original one, I havent replaced it, because it appears to still be working fine).. I even checked the air reserve box to make sure it was holding a vaccum.. Very frustrated, right before coming back inside, I recheck the check valves one more time. The one I replaced is free flowing both ways again! WTC??? I used no canned air, nothing other than me blowing or sucking (again, no need for comments).. Could it have been me? Or possibly did it happen right after I replaced it, and if so, what could be causing it? SO those questions along with, does anyone know a for sure way to tell if an actuator is bad? I hate to order one when I dont even need it, and this one seems to be holding a vaccum.. Im completely lost, could really use some fresh perspective. Thanks a ton guys....

 

XJcamaro is really the "go to" guy on this. I think I saw you post there too. It's very hard to realistically test the vacuum system without a gauge. Since you still have the original style solenoid you might replace that as it's relatively inexpensive, and easy to do. I know my truck needed both IWEs (one had a slow leak and the other had failed internally) and the solenoid when XJC helped me sort it out.