HOW TO: Diagnose your 4x4 system. ESOF
07-20-2018, 07:14 AM
#371
Hey guys. I'm having an issue and seems to be some pretty knowledgeable folks in here so i'm hoping you can help. I jacked the truck up to diagnose the IWE actuators on each side. Results are as follows:
Passenger Side - 2wd (CV Shaft Spins with wheel)
4wd (CV shaft spins with wheel, but I can turn continuously. Wheel does not lock)
Driver Side - 2wd (CV Shaft does not spin)
4wd (CV shaft spins with wheel, but I can turn continuously. Wheel does not lock)
I need to check and see if my solenoid has been replaced, but I did just have all hoses and check valves replaced. It would appear as though the passenger IWE is bad for sure. Driver seems good, but will probably replace anyway. However, the problem I'm stumped on is why when I'm in 4wd can I continuously turn the wheel? Every video I've seen, the wheels lock when trying to turn in 4wd. When I am driving, I can tell a noticeable difference in gear noise when I cycle between 2wd and 4wd. 2wd is loud and I can hear gears spinning. 4AUTO, things get quiet and sound normal. Does this sound like it could be my solenoid and IWE?
Any idea as to what is going on?
Thanks
Passenger Side - 2wd (CV Shaft Spins with wheel)
4wd (CV shaft spins with wheel, but I can turn continuously. Wheel does not lock)
Driver Side - 2wd (CV Shaft does not spin)
4wd (CV shaft spins with wheel, but I can turn continuously. Wheel does not lock)
I need to check and see if my solenoid has been replaced, but I did just have all hoses and check valves replaced. It would appear as though the passenger IWE is bad for sure. Driver seems good, but will probably replace anyway. However, the problem I'm stumped on is why when I'm in 4wd can I continuously turn the wheel? Every video I've seen, the wheels lock when trying to turn in 4wd. When I am driving, I can tell a noticeable difference in gear noise when I cycle between 2wd and 4wd. 2wd is loud and I can hear gears spinning. 4AUTO, things get quiet and sound normal. Does this sound like it could be my solenoid and IWE?
Any idea as to what is going on?
Thanks
Last edited by Blue2016XL; 07-20-2018 at 07:16 AM.
07-20-2018, 08:10 AM
#372
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Some clarification please. Are you putting it in 4 auto or 4h? 4wd will act differently between the 2. 4 auto will only engage the front wheels (I believe it is done in the Front diff but, could be at the TC) when the truck senses it needs to. The half shafts will always spin but, you won’t always have power applied to the wheel(s). 4H will send power to the wheels no matter what. Not the mode you want to be in on dry pavement because unlike 4 auto, 4H locks both front wheels together and won’t let them turn independently.
07-20-2018, 01:00 PM
#373
So you had the check valve and lines replaced so that rules those out unless the installer cracked a line. Verify that the connector that connects the line and the rubber hose coming from the IWEs are not cracked. Especially if they reused them.
With it going quiet in 4a, that just means something is not engaged because power to the front wheels isn’t being called for. It be interesting to see if the noise comes back if you can get it in the scenario where it sends power to the front.
if it was a vacuum leak, I’d expect both IWEs to not work as they both run off of the same vacuum line. This leaves as possibilities of:
1. One or both IWEs are bad
2. Front diff
3. Transfer Case
4. solenoid but, I’m not convinced this is it but, it is cheap and easy to replace.
One other possibility but, unlikely since it goes away in 4a is you have a loose bracket above 1 or both catalytic converters. Obviously check once everything has cooled off.
07-20-2018, 02:00 PM
#374
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Ok. Just wanted to make sure I/we understood.
So you had the check valve and lines replaced so that rules those out unless the installer cracked a line. Verify that the connector that connects the line and the rubber hose coming from the IWEs are not cracked. Especially if they reused them.
With it going quiet in 4a, that just means something is not engaged because power to the front wheels isn’t being called for. It be interesting to see if the noise comes back if you can get it in the scenario where it sends power to the front.
if it was a vacuum leak, I’d expect both IWEs to not work as they both run off of the same vacuum line. This leaves as possibilities of:
1. One or both IWEs are bad
2. Front diff
3. Transfer Case
4. solenoid but, I’m not convinced this is it but, it is cheap and easy to replace.
One other possibility but, unlikely since it goes away in 4a is you have a loose bracket above 1 or both catalytic converters. Obviously check once everything has cooled off.
07-20-2018, 09:32 PM
#375
Some clarification please. Are you putting it in 4 auto or 4h? 4wd will act differently between the 2. 4 auto will only engage the front wheels (I believe it is done in the Front diff but, could be at the TC) when the truck senses it needs to. The half shafts will always spin but, you won’t always have power applied to the wheel(s). 4H will send power to the wheels no matter what. Not the mode you want to be in on dry pavement because unlike 4 auto, 4H locks both front wheels together and won’t let them turn independently.
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Blue2016XL (07-20-2018)
07-20-2018, 09:34 PM
#376
Thanks, I'll keep you posted. I just picked up a new solenoid for $20 on the way to work. I'll get home and swap it out tonight and see if I get any different result. I know for a fact the passenger side IWE is shot, so I just ordered 2 new ones. Figured if one is gone, its only a matter of time on the other.
07-20-2018, 09:50 PM
#377
Not quite. The connect / disconnect for 4A on demand happens in the TC. When in 4H, it's not the front wheels that are locked together (other than an option on the new Raptors, the front differential on 4x4 F150s is of the open type). It's the front and rear drive shafts that are locked together. You still should not use 4H on dry pavement, and for the same reason you are alluding to, but that's a critical difference.
Thanks for making the distinction. My mistake in explaining it.
07-21-2018, 09:31 AM
#378
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Thanks guys. I got the solenoid in last night. It didn’t appear to make a difference, but I need to get under the truck and re diagnose. 2 new IWE’s are on the way so should be able to swap them in next week
07-21-2018, 03:19 PM
#379
This has been a great resource but I am not quite sure what to do at this point with my situation. I have replaced the check valve and just recently had the drivers side CV shaft replaced (leaking) and had them check the 4wd system operation because I had suspected it was malfunctioning. Well, they reported the system was in perfect working condition but I had my doubts still. I just cycled the system and tried 4L to see if the TCM was working and it did engage 4L. Well I decided to stick a GoPro and watch each CV axle and the front driveshaft. I just saw the video and everything turns while in 2wd. Just to be clear, when my selector is in 2wd it seems that the entire system is engaged in 4wd. Any thoughts on how to proceed? I have read the diagnose guide multiple times but I think I am just not even sure where to start at this point. Thanks everyone.
07-21-2018, 04:23 PM
#380
I did a little more testing.
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.
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.