Yup, that sounds like the solenoid is not working.. Replace that, and see if you get true 2WD back..

 

same noise as who's?

instead of just throwing a new solenoid at it, pop a line off between it and the engine to make sure the engine is pulling vacuum. then check the other side of the actuator and see if there is vacuum with the truck idling in 2wd.. if there is, keep moving down and check the reservoir box hidden behind the battery (mine was busted apart), then the wheel actuators. cheaper (and just as easy) than throwing parts at it.

 

Hi Folks! Based in the info of the excellent tread (Thanks XJCAMARO89) I checked the wheels and driver side it's disengaged at 2H, passenger side it's alway engaged. Also found the 12V at the solenoid it's always present in 2H or 4H but in my innocenter show the warnings 2H or 4H check 4X4 then I asume the with it's working properly.

I conclude 1 have 2 problems.
1) Maybe a Vacum or fail actuator in the passenger wheel
2) The 4X4 command signal to the solenoid it's not working properly.

I need help to isolate the #2. Any idea?

TIA!

Art Garcia

 

I haven't read all 26 pages of replies, but the initial post was a good read. I'll have to see if it's all the same for the AWD system on the '08 Limited. I can't imagine it would be much different, if at all, maybe just some different commands from the computer. I think the computer automatically kicks in the front wheels when it detects slippage from the rears.

 

Great write-up!

I replaced my vacuum hoses between the solenoid and the actuators about 3 years ago. This past weekend I replaced both actuators and swapped out the original solenoid for the "updated" solenoid with the hood.

Before I bolted everything up and put the wheels back on, I checked the new actuators to see if they worked by starting the truck and connecting/disconnecting the vacuum line at the actuators. Everything worked fine and the actuator gear moved inward and outward like it's supposed to.

I still get these random noises from the front end, as if it's trying to engage the front wheel(s). I notice the noise with my foot off the gas and I'm slowing down to a stop. I don't really notice the noise at any other time.

I've ordered two new check valves (to be delivered in two days) and hopefully they solve my problem, as I'm thinking my current check valves are leaking and letting the vacuum drop in the lines when the vacuum from the engine drops. Guess I'll find out in two days.

 

Did you ever get the problem fixed. Mine does the same, No 4H light but I do get the 4L light

Thanks for the help

 

have you inspected the vacuum reservoir behind the battery? mine was all busted.

 

Just popped in to say THANKS to all the contributors in this thread. I was able to quickly troubleshoot and repair my IWE/4WD problems. In the process I become a lot more familiar with exactly how these systems work as well, which is always a good feeling!

 

I have a few new things to try since reading your post. My 07 supercrew 4x4 is making the clicking on the front driver side. I jacked up the front and everything works fine. When get on the road at idle all is well. Only after you give it gas does the clicking begin. you can let off the gas and it will stop. After reading it sounds like it could be a check valve or possibly the vacuum reserve box. What do you think?

 

I'm hearing the same grinding noise and voltage gauge goes up to 3/4. My 4x4 light does not come on, no other lights come on. Replaced drivers side actuator and vacuum switch on the firewall, check all the vacuum lines and bank behind the battery, still does it. Any help?????? Seems to do it more when it's wet out or very cold at low rpm's.

 

check and replace all the one-way vacuum valves along the firewall to the right of the ESOF solenoids. there's like 3 of them.. your losing vacuum off idle to the IWE's

 

This is very similar to what mine was doing. I had a combination of problems, bad check valve, cracked lines (in the wheel wheel) and lots of water in my drivers side IWE.

 

Just stopping to by to see how everyones IWEs were doing. Im glad this thread after so many years has helped so many. Since the article was written I moved on to a 2007 Screw and never had an issue with the IWEs and recently moved up to a 2012 EcoBeast.

 

I have a problem no one has mentioned so far. I have the grinding noise coming out of the passenger side only. I have low vacuum on passenger IWE hose only 6 inches and 26 on the drivers side. Couldn't find any leaks? What could cause a low vacuum reading on the one side only?

 

There are several check valves in those lines that help hold the vacuum during the change with engine load. If a check valve in line to just that side is bad it could be letting the vacuum drop too far. Or if you have a leak on just that side somewhere. The check valves for the other side would keep that side from dropping. I found its hard to check for leaks based on the routing of the stock lines. What you could do to test it is take a long piece of rubber vacuum line and run it from up by the solenoid straight down to the actuator and see if that fixes the issue. If it does then you have a leak somewhere. I would connect your test line in after the check valve for that side so then if the problem is still there then you can by pass the check valve and see if the problem is still there. If it isn't at that point then its probably the check valve.