I have an 07 f150 supercrew 4x4 and am having some 4wd problems that the dealer isn't diagnosing. During the last snow, I would back out of the driveway and while rolling down the street i would turn the shift on the fly 4wd **** to 4WH. As soon as the light comes on, I take that as a green light to get nasty. So I would give the tires a few revolutions and then hit the gas. Shortly after, there is a loud bang from the front end and the truck fishtails. I can let off the gas and get back on it a couple of times and then the 4wd will hold. I only hear one loud bang as it drops out each time, not grinding of any kind. Once the 4wd has finally hooked up and stayed in, it appears to be ok for the duration of that trip to engage and disengage.

I took the truck to the dealer and they said they pulled no codes and saw nothing wrong. I have no idea how far they dug into the problem. My warranty will be up tomorrow on my way to work, but they did agree to hold the service ticket open for 30 days. Basically I have 30 days to prove that somethings wrong.

Has anyone had this problem? Maybe I can point out the failing component to the dealer for a better inspection. What's covered on the 36,000 mile warranty vs the 60,000 mile warranty? If it's a lock-out (as I think it is), will that be covered on the 60,000 mile warranty? I don't know what specific parts are covered on the powertrain warranty vs the bumper to bumper.

Thanks for the help!

 

if you reported the problem to the dealer before your warranty is up and they failed to duplicate the problem or repair it, it will still be coverd under warranty. It sounds to me like their is a vacuum leak in the IWE system or a bad IWE solinod or an IWE itself. Id suggest looking for a different dealer that knows how to properly diagnose this sytem... Their is things that go wrong with this sytem all the time that dont set "DTCs", and if all your dealer did was scan it and say "nothing wrong" go somewhere else.

 

I've had the same thing, no matter what the light says it seems to take a bit for it to engage or disengage. If I just flip the switch and punch it yes it will slam into engagement after the rear wheels slip pretty good, but I normally don't do this so it hasn't been an issue.

Considering how quickly the light goes on or off, I suspect it isn't a true indication of if you are in 4X4 or not but rather what position the switch is in. I've never owned a 4x4 that engages as consistantly quick as the light would lead you to believe, and I know it isn't always engaged or disengaged as quickly as the light says it is. But this doesn't strike me as unusual for this type of 4x4 system.

edit: Maybe this isn't quite what you were saying, but it's so similar I'm still wondering if it is the same thing.

 

It's one of those things where you wonder if you're going to have a failure just as soon as you hit 36,000 miles. Perhaps I'm just being too rough on the 4wd and expecting it to lock in immediately. It seems like the issue is that one of the IWE's is not locked in fully and is kicking out. Either it's taking some time to engage fullly or I'm just being unreasonable and hitting it too soon. I don't know what this mechanism looks like. Is it a splined sleeve that slides to lock two splined shafts together? Can they get sticky?