Im hearing this grinding noise which sounds like heat shields rattling. when in 4x4 it goes away then back in 4x2 it comes back.. it rattles when the engine is under moderate load in low rpms.. would this point out that it could be a vacuum leak.

I already replaced the IWE solenoid which came out to $92 of a waste, (didnt change nothing)

I blew out all the lines and hubs nozzles with compressed air which didnt do nothing....

Anyway if i just unplug the solenoid its all good but then the front axle and driveshaft is spinning.

My Questions:
1) Would it be better to to just leave the soleoid unplug until i get the problem fixed? ( im going down to Detroit from toronto on sunday and i dont want it grinding the whole way)

2)how do i fix the problem/How much money??

Thanks Everyone

 

sounds like a vacuum leak. could either be lines or one of the wheel ends themselves. also there is check valves in the lines that can seize if water has gotten in the lines.

 

Mine made that noise last summer, I tried lots of things, when I changed the trans case oil it got quiet, but when I used 4WD this winter it broke. All the IWE splines were worn off, and the opposite splines on the hubs were toast too. I spent about $800 on factory parts and employee labor at the independent repair shop where I am a counter guy. In retrospect, I could have done the repair but I didn't trust myself. If you pull the hubs I bet it's the same thing, sorry to tell you expensive news.
I think the noise happens under load when the vacuum drops off and the hubs partially engage. What a crap design.

 

More than likely you have a vaccum leak. Check to make sure the line hasnt melted agaisnt the right hand exhaust manifold. Common problem. Good luck.