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Each vacuum line at the IWE has about 20'' vacuum. In 2wd I jacked up each side and tested the wheel spin. Both CV shafts do not rotate with the wheel while the engine is running. This tells me that the IWE's are not the problem.
I also did both tests for the TC and TCM and both function just as the diagnosis procedure states. I will say that spinning the front drive shaft in 2wd did turn the CV axle when I performed the test. So, the TC and TCM are not the issues either.
So, if the TC/TCM are functioning correctly and it seems like the IWE's are not engaged while in 2wd. What could be causing everything to seem to be engaged 4wd while in 2wd? Something, somewhere is engaged to make this system show this behavior.
I haven't done a video myself to see how mine are as I don't have the equipment. However, I have read that you may still get some movement of the half shafts even when disengaged. My guess they probably shouldn't be spinning as fast as they would be if engaged though. Post the video if you can. It is possible that something could be sticking periodically/frequently but, not all the time. Question, when you did the tests, was it in the morning before the truck was driven or after? Try the test again when everything is at the same temp (or at least as close to as you can get) and see if you get different results. Or randomly pick times to test it.
You never said but, under the assumption you did, did they engage when you switch to 4wd? Then disengage when you switched back to 2wd? Maybe repeat that a few times to see if you get 100% engagement and disengagement or maybe one time you don't.
Hey guys. Just wanted to give y’all an update. Got my new IWE’s in today. Finally got some time tonight to tear into it. I started on the passenger side and sure enough that IWE was toast. The plastic ring and gear completely snapped off and separated from the rest of the IWE. It’s no wonder why I was having issues. I replaced driver side too. Everything looked good on that side, but figured I’d replace it anyway. 2x4 and 4x4 work as intended.
Picture below shows the new IWE and the old, broken IWE.
I haven't done a video myself to see how mine are as I don't have the equipment. However, I have read that you may still get some movement of the half shafts even when disengaged. My guess they probably shouldn't be spinning as fast as they would be if engaged though. Post the video if you can. It is possible that something could be sticking periodically/frequently but, not all the time. Question, when you did the tests, was it in the morning before the truck was driven or after? Try the test again when everything is at the same temp (or at least as close to as you can get) and see if you get different results. Or randomly pick times to test it.
You never said but, under the assumption you did, did they engage when you switch to 4wd? Then disengage when you switched back to 2wd? Maybe repeat that a few times to see if you get 100% engagement and disengagement or maybe one time you don't.
Just some thoughts.
Thank you for responding!
I have some videos but I will figure out how to post them. I guess I haven't thought about how fast the shafts are spinning but they do appear to be turning the same rate when fully engaged in 4wd. When I did move the selector to 4wd the hubs did engage and they did disengage when I put it back into 2wd. The tests were done at normal operating temperature after running some errands when about 85 ish degrees out.
I would think that maybe I am getting partial vacuum loss somewhere but when I recorded the cv's I did it in reverse, slow forward movement as well as normal driving range. In all of those cases the cv's were turning.
My thought is that it has something to do with the transfer case. I tested its operation and I can achieve 4wd and 4lo. I am thinking that when returning to 2wd there must not be a complete disengagement of the transfer case. I think this is the cause (or maybe something electrical?) because the front dive shaft and the cv's must be getting some form of resistance to make the whole system rotate, right? If the IWE's are both disengaging at the wheels then there is no other way for the system to rotate? The only other input would have to be from the transfer case. At least, I think? Lol.
I have some videos but I will figure out how to post them. I guess I haven't thought about how fast the shafts are spinning but they do appear to be turning the same rate when fully engaged in 4wd. When I did move the selector to 4wd the hubs did engage and they did disengage when I put it back into 2wd. The tests were done at normal operating temperature after running some errands when about 85 ish degrees out.
I would think that maybe I am getting partial vacuum loss somewhere but when I recorded the cv's I did it in reverse, slow forward movement as well as normal driving range. In all of those cases the cv's were turning.
My thought is that it has something to do with the transfer case. I tested its operation and I can achieve 4wd and 4lo. I am thinking that when returning to 2wd there must not be a complete disengagement of the transfer case. I think this is the cause (or maybe something electrical?) because the front dive shaft and the cv's must be getting some form of resistance to make the whole system rotate, right? If the IWE's are both disengaging at the wheels then there is no other way for the system to rotate? The only other input would have to be from the transfer case. At least, I think? Lol.
At this point it is going to be hunting game unless you can confirm that the half shafts are not spinning as fast as they are when engaged. What I would do is video when not engaged and then while still moving and recording engage 4wd. If you have sound honk the horn when you do it so that you have something that indicates you switched it while viewing. If they aren’t, then I am not sure you really have an issue.
At this point it is going to be hunting game unless you can confirm that the half shafts are not spinning as fast as they are when engaged. What I would do is video when not engaged and then while still moving and recording engage 4wd. If you have sound honk the horn when you do it so that you have something that indicates you switched it while viewing. If they aren’t, then I am not sure you really have an issue.
I would think that either way I would have an issue. Based on what was stated at the beginning of this thread:
So, in 2WD, nothing in the drivetrain (front driveshaft, differential, half shafts) spins at all. When you turn the ESOF switch to 4Hi, a couple things happen simultaneously. First, the TCM moves the lever in the TC to the 4Hi position. This engages the front driveshaft, with the internal TC clutch spinning it, the differential, and the half shafts up to speed very quickly.
I would think that either way I would have an issue. Based on what was stated at the beginning of this thread:
So, in 2WD, nothing in the drivetrain (front driveshaft, differential, half shafts) spins at all. When you turn the ESOF switch to 4Hi, a couple things happen simultaneously. First, the TCM moves the lever in the TC to the 4Hi position. This engages the front driveshaft, with the internal TC clutch spinning it, the differential, and the half shafts up to speed very quickly.
All I am saying is that I've read on here somewhere that you still may get some frictional movement when in 2wd of the half shafts. Whether that is true or not, I can't say.
Your next step is to.get a vacuum gauge on the lines @ each IWE, one at a time, to see if there is vacuum there in 2WD, engine running. Sounds like your IWEs are always engaged, which costs you fuel mileage.
When checking the vacuum (with the engine running), how many pounds is it supposed to be pulling at the input side of the solenoid (from the engine side)? From the output side of the solenoid? At each IWE?
I've been dealing with a grinding noise on my 2010 F-150 Lariat and it's coming from the transfer case. When it's not under-load (i.e: up on a lift), the wheels spin free in 2WD and all the front driveline works normal when in 4WD (and again, not underload).
I've replaced the transfer case, wheel bearing assy's, both IWEs, and both calipers...and I'm still getting a grinding (rock-crushing) noise from the TC intermittently between 20-25mph to 50-55mph (usually at 26 mph-ish, 38 mph-ish, and 45 mph-ish).
I'm beginning to think that the front drive-line is intermittently engaging at those speeds...but of course, I don't know for fact. I'm thinking of using three short (maybe 6") length of fishing line with a small weight on them and securing them to the front axles and front driveshaft to see if they wrap around the shaft and axles after driving a short distance.
IWE's remained unlocked for a little while, but are now locking again. If I pull the vacuum line off at the check valve with the engine running, draining the reserve box, and re attach they unlock again. I had my wife switch into 4x4 while I touched the solenoid, I could feel it click and then vent vacuum. When she switched back to 2wd i did not feel anything and the IWE's remained locked. This happened with 2 different IWE solenoids. Could the ESOF switch not be communicating with the solenoid when placed back into 2wd?
Theres a lot of info on here and I have not read it all. I have become my own expert with this system and fix - service and repair them all on my own now with little effort.
What I will say to everyone on here - especially those who say the grinding sound only happens when they are turning...
The vacuum lines are attached to the spindles with a snap fit hose clamp type bracket. This is the first thing everyone must check.
Both of my sides cracked right where they are secured to the spindle at this point. Make a turn, the cracks open up = vacuum loss = grinding sound or partial engagement.
You can go spend a ton of money replacing the hoses and changing out the IWEs or you can just cut the lines and splice in a couple of hose couplers which can be found for a few bucks and problem is solved.
IWE's remained unlocked for a little while, but are now locking again. If I pull the vacuum line off at the check valve with the engine running, draining the reserve box, and re attach they unlock again. I had my wife switch into 4x4 while I touched the solenoid, I could feel it click and then vent vacuum. When she switched back to 2wd i did not feel anything and the IWE's remained locked. This happened with 2 different IWE solenoids. Could the ESOF switch not be communicating with the solenoid when placed back into 2wd?
It could be the switch, but before changing that out, check out the connector. Maybe try the same thing again with your wife, and if it doesn't throw over, gently move the connector around while you hold a finger on the solenoid. Seems I recall at least one other member that had a bad connector.
07-21-2018, 05:53 PM
