2013 Raptor - Do I have a major diff problem?

[DreamcastERA]

definitely sounds like a vacuum leak. what happens when you put it in 4 wd? does the sound go away?

That does appear to be the problem - I got a dorman IWE actuator (just because it's all that I could get on short notice) and my driver's side hub is now unlocked when in 2WD (as it should be). I even paint marked the axle and IWE to make sure its hasnt moved after I've driven somewhere. However I did get the rattling / grinding noise once again. It only happens under load, so I'm beginning to think that the check valve has gone bad. Specifically because as engine load increases, vacuum decreases. So if the check valve is failing then the vacuum applied to my hubs will decrease with engine load. Since it's so cheap, I also bought a replacement solenoid. I have not tested for vacuum leaks yet because I just haven't had the time. However, it definitely pulls and holds enough vacuum (at low speed/load conditions at least) to keep the hubs fully unlocked. I have also inspected all of the lines and haven't found any obvious breaks - but it's pretty tedious to follow it all the way from the hubs to the vacuum reservoir ... haha

Forgot to mention! The sound DOES go away on 4WD - or if I remove vacuum and unplug the solenoid. But I don't want to do that even temporarily because it appears to have already caused diff damage.

 

[DreamcastERA]

Personally, I would not. The system works very well as designed, and has been for the decades since it was introduced. The intent is to reduce parasitic drag and eliminate unnecessary wear on the front driveline components. Meaning the front differential, CV axles, transfer case, and propshaft. Ford is the only OE to use that system, and I give them credit for sticking with it while everyone else has used constant engagement front axles.

Not sure what you mean regarding breaking a race on the CV axles?

I would generally agree. I also watched someone report back about wear issues after running the RCV eliminators for a few months (I think it was just under a year ? not sure how many miles).

Regardless of whether or not I'd run eliminators, I really shouldn't at the moment because there already appears to be significant diff wear

 

[DreamcastERA]

I would be surprised if the differential is not severely worn and damaged due to only one axle being engaged. When one axle is turning and the other is not, the differential side gear on the engaged side will be spinning at wheel speed, along with the pinions. The opposite side gear remains stationary. These gears are only designed to accommodate for wheel speed differences when turning, and not for one side spinning at road speed while the other remains stationary. When the side gears wear, the axle will exhibit radial movement, which destroys the axle seal and causes an oil leak.

As far as the IWE replacement, it is critical that the Ford published service procedure be followed. I’ve seen far too many repeat repairs due to improper installation. The wheel hub nut (axle nut) must also be replaced as well, they are not reusable once removed.

That makes sense - just to be clear - would that cause the wear to increase many many times over? and would that likely require a rebuild that includes replacement spider gears and bearings?

Also, even with a new seal - would that excess radial movement cause enough wear to the point that a new seal would not seal properly anymore?

 

[DreamcastERA]

Boot might of had a leak, didn’t notice before taking it to the off road park though. last time I go into the Rock Garden…like I said I wouldn’t…but did.

View attachment 348738
Pretty sure this is when it happened. Used front camera and looked like I could make it down, turns out there was a false summit. Should have gotten out to look, or brought a spotter. Live and learn!

Just to add to it all - my passengers side CV has developed a tear in one of the boots!

 

[DreamcastERA]

Make sure those numbskulls put loctite on the axle nut and that it is torqued to spec. Have them perform a vacuum test on the iwe system at the same time. You don't want to go back a 3rd time. Unfortunately these days a little be of proactive knowledge shared with a mechanical shop goes a long way. Hope they fix it correctly this time. Keep us posted.

That's also good to know. I did not know that those nuts are not considered reusable - I'll ask them about that. Is that something I could just replace with the vehicle sitting on the ground - or is it meant to only be replaced with no load on the suspension?

 

[FordTechOne]

That makes sense - just to be clear - would that cause the wear to increase many many times over? and would that likely require a rebuild that includes replacement spider gears and bearings?

Also, even with a new seal - would that excess radial movement cause enough wear to the point that a new seal would not seal properly anymore?

Yes, if the side/pinion gears are worn, it will require a rebuild or replacement of the differential. Worn differential gears will cause a repeat failure of the axle seal.

 

[DreamcastERA]

Yes, if the side/pinion gears are worn, it will require a rebuild or replacement of the differential. Worn differential gears will cause a repeat failure of the axle seal.

Nice, I have the truck scheduled for a visit to a shop with a good reputation that only does differential work - they're just not available for a couple months. Hopefully I can just the hub actuation issue solved so that I'm not causing further damage in the meantime.

Potentially ignorant question: I understand why the side gears would need replacement , but why would the pinion also need replacing? Is the uneven load enough to cause significant uneven wear on the pinion gear itself? And if so - would that also likely warrant a new ring gear?

 

[CoronaRaptor]

That's also good to know. I did not know that those nuts are not considered reusable - I'll ask them about that. Is that something I could just replace with the vehicle sitting on the ground - or is it meant to only be replaced with no load on the suspension?

I've never heard of it being done with the tire on or it on the ground. Tire off and lower control arm supported. @FordTechOne would know the proper proceedure.

 

[Jakenbake]

I've never heard of it being done with the tire on or it on the ground. Tire off and lower control arm supported. @FordTechOne would know the proper proceedure.

If you center caps are removable with the wheel on, you might be able to.

Just for what it is worth, mine have been off and on a few times. Not advising for others to do as I do though.

 

[DreamcastERA]

Man, I have just not had a great week!

I was very low on gas when I pulled up to a gas station after work, I left the truck running (like I always do) and started to fill up - seconds later I heard my engine struggle and die and looked in horror to see a Low Oil Pressure warning on my dash! I checked my oil level and for any leaks - all good. I really had to work myself up to restarting the truck but when I did it kinda struggled as if it had run out of fuel, and then it was fine again! Drove it the rest of the way with no noticeable fuel mileage or power loss. It's also not making any weird noises (beyond the rattling/grinding under load we already know of). I assume I ran out of fuel literally at the gas station and as the truck stalled it triggered the low oil pressure on its way down. Scared me to death haha

That combined with the fact that I may not be able to drive the 300 miles home in a few days if I don't get this 4WD issue figured out has been fun ! (And also, if you watch soccer, my Chelsea lost to Brentford of all teams by 3 goals!)

God is good though - engine seems fine now and I have the check valve and solenoid set to arrive on Tuesday. Hopefully that solves the issue and I can deal with the diff rebuild later.

Thank all of y'all for your help