School me on IWE's
10-13-2018, 03:50 PM
#31
I spoke with my service manager about it and it was apparent he didn't understand the system well at all. I outlined my test procedure again, and they agree that in those conditions they should disconnect. They are now trying to do some more research on it and will get back to me. Either way, they didn't get replaced. They stated they could get the back wheels to break free without the fronts turning (yah, no ****, because the T case isn't engaged), but it sounds like they didn't do what I did to replicate it. Either way I'm not sure how long I've felt its been like this, a few months? Maybe since the beginning of the year? I've only noticed the tires wearing this summer though. I've never had the grinding or anything so that would tell me its a complete failure, not a partial as they are just engaged and not partial. Will update once I get some more info too, but I still feel this is not working correct.
I'm not sure what some of you are saying in here though, the system seems pretty simple to me. 4a engages T case clutches that transfer power, 4 a has the ability to disconnect on the power side. 4H will always remain connected on the power side. IWE actuators are connectors on the passive side, allowing the wheels to disconnect from the output shafts from the dif. 4a engages these all the time and the t case clutch modulates the power. 2H should disconnect the shafts so they aren't being turned statically by the wheels, and with the t case disengaged nothing in the front should be turning. Both t case and IWEs need to disconnect to be 2H, if just the T case disconnects its just like driving around with manual hubs in "lock"
I'm not sure what some of you are saying in here though, the system seems pretty simple to me. 4a engages T case clutches that transfer power, 4 a has the ability to disconnect on the power side. 4H will always remain connected on the power side. IWE actuators are connectors on the passive side, allowing the wheels to disconnect from the output shafts from the dif. 4a engages these all the time and the t case clutch modulates the power. 2H should disconnect the shafts so they aren't being turned statically by the wheels, and with the t case disengaged nothing in the front should be turning. Both t case and IWEs need to disconnect to be 2H, if just the T case disconnects its just like driving around with manual hubs in "lock"
10-13-2018, 04:37 PM
#32
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I'd say you have a good understanding, don't let anyone tell you different. 
10-22-2018, 05:56 PM
#33
Senior Member
Little late to the party here... ever since I got my 2015, it seems like i've been having issues with the 4wd system. Already had the driver's side IWE replaced, and now hearing that same intermittent growling again, which disappears in 4A mode. Also 4A/4H are significantly louder than 2wd.
Also, i've always sort of had a front-end whirring noise that I couldn't seem to get the dealership to figure out. Anyway... as the weather's gotten colder here recently (VT), the front-end's been acting up a little more regularly.
Since I needed an inspection, I figured i'd make (yet) another appointment. This time though, I had my daughter drive the truck forward slowly in 2WD mode, and I stuck my cell phone inside the wheel well, and was able to get a video of the driver's side (front) axle shaft turning.
Also, the front driveshaft was definitely turning as well. Not saying it's necessarily the IWE, but something in the system is acting up. Anyway, showed this video to my service advisor today, and sure enough, they think the 4wd system is fine, but the front diff is toast.
I've been driving with it like this for a while, so maybe having one axle shaft turn and the other stationary has burned up something in the front diff (spider gear bearings?)
The dealership is supposed to have the parts in tomorrow for a front-diff rebuild. Will see what they say, but to make sure they checked it, I called back and requested they inspect the complete vacuum system.
I don't see how a front diff just goes bad... but maybe it's always been that way? I just changed the fluid in that thing recently (cheater suction method), and it didn't seem like the fluid was loaded with metal particles.
Also, i've always sort of had a front-end whirring noise that I couldn't seem to get the dealership to figure out. Anyway... as the weather's gotten colder here recently (VT), the front-end's been acting up a little more regularly.
Since I needed an inspection, I figured i'd make (yet) another appointment. This time though, I had my daughter drive the truck forward slowly in 2WD mode, and I stuck my cell phone inside the wheel well, and was able to get a video of the driver's side (front) axle shaft turning.
Also, the front driveshaft was definitely turning as well. Not saying it's necessarily the IWE, but something in the system is acting up. Anyway, showed this video to my service advisor today, and sure enough, they think the 4wd system is fine, but the front diff is toast.
I've been driving with it like this for a while, so maybe having one axle shaft turn and the other stationary has burned up something in the front diff (spider gear bearings?)
The dealership is supposed to have the parts in tomorrow for a front-diff rebuild. Will see what they say, but to make sure they checked it, I called back and requested they inspect the complete vacuum system.
I don't see how a front diff just goes bad... but maybe it's always been that way? I just changed the fluid in that thing recently (cheater suction method), and it didn't seem like the fluid was loaded with metal particles.
10-22-2018, 07:04 PM
#34
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Sounds to me, you need to teach your dealer a few things. You're correct in what you're saying. I believe I'd also be sure to let them know what you found, and how to troubleshoot the system.
And those guys get paid? I'm usually pretty laid back, but sometimes I do let go, those are the types I like to let go on.
Is there another dealer you could go to? I don't think I'd be comfortable with those guys vacuuming out the backseat.
And those guys get paid? I'm usually pretty laid back, but sometimes I do let go, those are the types I like to let go on.
Is there another dealer you could go to? I don't think I'd be comfortable with those guys vacuuming out the backseat.
10-22-2018, 09:02 PM
#35
Senior Member
It pains me to admit that I keep going back to this place, from the service perspective. It has gotten better in recent years, but still not where it should be.
I suppose I could go pick up my car tomorrow, and skip having them do the front-diff rebuild, but I suspect any other dealership is going to take their word for it. Put differently, if one dealership says the diff is cooked, is another dealership going to feel like they need to re-diagnose it?
This dealership is much more convenient for me location wise, and I've purchased two f150's from them.
I guess we'll see what they say tomorrow, I just feel like I'm expecting to be disappointed. That said, a complete vacuum system, less IWE's isn't too much more than $50 from Tasca, is it?
I suppose I could go pick up my car tomorrow, and skip having them do the front-diff rebuild, but I suspect any other dealership is going to take their word for it. Put differently, if one dealership says the diff is cooked, is another dealership going to feel like they need to re-diagnose it?
This dealership is much more convenient for me location wise, and I've purchased two f150's from them.
I guess we'll see what they say tomorrow, I just feel like I'm expecting to be disappointed. That said, a complete vacuum system, less IWE's isn't too much more than $50 from Tasca, is it?
10-22-2018, 10:05 PM
#36
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The only thing you need other than the IWEs are a ckeckvalve and a solenoid, plus the hoses. Here's the new updated parts for the valve; https://www.tascaparts.com/oem-parts...ube-fl3z3a788a And if you look through their parts the solenoid would be there as well.
I think I'd start with the hose/checkvalve. It sounds to me like you still have an IWE locked in. As you found, that's why your half shaft is turning, and in turn, your front diff and driveshaft all the way into the Tcase.
I gotta say more/less again, you know more about it than your dealer.
If you were to go to another dealer, try explaining calmly why you're there. A bad service dept is no secret to these guys.
Let us know what happens if you will.
I think I'd start with the hose/checkvalve. It sounds to me like you still have an IWE locked in. As you found, that's why your half shaft is turning, and in turn, your front diff and driveshaft all the way into the Tcase.
I gotta say more/less again, you know more about it than your dealer.
If you were to go to another dealer, try explaining calmly why you're there. A bad service dept is no secret to these guys.
Let us know what happens if you will.
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Fatmattyd (10-23-2018)
10-22-2018, 10:12 PM
#37
I could see if only one side was stuck and turning the front diff that it would cause the diff to run in a way it wasn't designed for, for long periods. I believe someone else on the forum has had their front diff go as well. Who knows. you may have nothing wrong with the IWE and it is the front diff that is causing the shaft to turn. Everyone goes straight to the IWEs when the grinding starts. Why? Because, that is the are that usually fails (IWE themselves, check valve, solenoid or a hole in the line). I haven't seen a lot of threads where the front diff went bad. Same with the Transfer Case.
10-22-2018, 10:43 PM
#38
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10-23-2018, 01:54 AM
#39
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Same problem here with intermittent vibration/humming in 2wd. Dealer replaced front hubs after I replaced check valve and solenoid in the spring. I verified the front half shafts disconnect when there is vacuum but maybe there is still enough friction to get them spinning. Seems like the vibration occurs when slowing down until the truck comes to a complete stop. When I switch into 4A I get other whirring and rumbling noise/vibration that doesn’t seem quite right either.
10-23-2018, 08:31 AM
#40
Senior Member
Yeah - similar symptoms here. Also, I had previously changed the check valve, super easy to do.
I'll update later today if the dealer gets my front diff rebuilt. I'm hoping that the consistent humming/whirring goes away after that.
I'm just concerned that i've got a bad IWE as well. Still doesn't seem like a bad diff would cause the front driveshaft and drivers side axle shaft to turn when in 2wd. The entire front driveline should be disconnected when in 2wd. Front driveshaft not being powered by the transfer case, and front wheels disconnected from the axle shafts by the IWE's.
I'll update later today if the dealer gets my front diff rebuilt. I'm hoping that the consistent humming/whirring goes away after that.
I'm just concerned that i've got a bad IWE as well. Still doesn't seem like a bad diff would cause the front driveshaft and drivers side axle shaft to turn when in 2wd. The entire front driveline should be disconnected when in 2wd. Front driveshaft not being powered by the transfer case, and front wheels disconnected from the axle shafts by the IWE's.