So recently I've been having 4x4 problems. Its happened 3-4 times in the last couple weeks I'm driving along and my drivers front wheel starts making grinding metal noises like its trying to engage 4wd. I pull over cycle my 4x4 till engaged, go back to 2wd and its fine. Now when I shift into 4x4 high I hear/feel no engaging but 4x4 low works fine. My vacuum lines seem fine with no leaks. Any ideas? With no 4x4 high and only low working it couldn't be a vacuum problem right? Any ideas

 

If its trying to engage like that going down the road, your actuator might have a weak spot and small leak. I would whip out the vacuum pump and start testing your actuators and check valves. Have you upgraded the solenoid on the firewall?

 

Nope I haven't. 2008 lariat also

 

There is a chance its the solenoid. The upgraded one has a rain shield to help keep water out. Solenoid might be trying to short..

 

Is the solenoid the same as the iwe? How much would a new solenoid cost

 

the solenoid is like $40

 

Iwe is the system. Its called the IWE Solenoid. Just for s&GS take a look at your check valves. You should be able to blow through them but not suck back in. Remember which way you pull the check valves. They gave to be reinstalled the same way. Follow the vacuum line from the solenoid on the firewall and you should find two.

 

My check valves and lines seem good. It still won't lock into high but 4x4 low works perfectly

 

Solenoid would be next.. if you have a voltmeter, see if you have any change in voltage compared to when you are in 4 low

 

I actually think you may have 2 issues going on here, but I'm guessing...

If you're getting the grinding noise in 2WD going down the road, it sounds like one of your IWE's is likely failing. Get a vacuum pump and test if possible. You'll know right away, it's either going to hold vacuum or it's not. If you don't have one easily available, drive until it's grinding, stop, pop the hood, pull the vacuum line to the IWE solenoid and see if it goes away. If it does, it's probably an IWE and you've basically forced the truck to lock the hubs. That'll tell you if this issue is right or wrong.

As for the second issue, it sounds like it "might" be the IWE solenoid failing and providing a false reading... but I'm not 100% sure on that. What symptoms are you seeing? Is the 4x4 High light coming on? Is it not? Are you able to clearly tell when you're driving that it's not in 4x4 high (especially if the light is off?). I had an IWE solenoid that was forced open and would actually show 4x4 high (transfer case would shift) but not actually stop vacuum. This did the opposite though, it told me I was in 4x4 High but the hubs stayed unlocked so I didn't actually have it.