Attached three photos of front differential. Photos were taken while I was behind the driver's side front tire with the camera pointing towards passenger side.

There's a gray colored fluid leaking out between the where the passenger side tube housing bolts to the case. The fluid glows fairly brightly when a blacklight illuminates it. It looks like the leak is originating directly below one of the bolts; I wonder if that specific bolt could be tightened more if this is truly where the leak is? Not sure if the factory sealant has failed or what exactly.

Thank you for helping

2013 EcoBoost crew cab, 4x4, 58K miles, no modifications.

 

Alright chum, you are in for a treat.
The tube is sealed with silicone from factory and is held by 4x bolts. I don't know if you can remove that tube without taking the entire assembly out but either way you will have to remove the CV joint and everything in front of it (knuckle, brakes, etc..) to free the tube. I don't know how mechanically inclined you are or how many tools you have but I will tell you two things.
1- The gray liquid is your diff oil mixed with water. Even if you don't do any off-roading, condensation is getting into the diff and because we don't use the 4x4 often, it just accumulates as it stays stationary unless the 4x4 is engage.
2- If you end up having to remove the front differential assembly, you DON'T have to remove the rack and pinion or even disconnected the steering shaft from the said rack and pinion like it's mentioned in the manual. With the proper tools and extensions you can access all the fasteners you need and will save you an alignment at the detriment of taking a little more time.

If you decided to pull the entire assembly, it will take you about 6h if your vehicle is on jack stands and you have access to pneumatic or electric tools. I would also recommend to replace the front diff cover with the one with a drain plug from purple cranium (https://purplecranium.com/i-63199-fo...o-mustang.html) while you're at it. It will make the next service super easy.

If you go with the assembly pull, buy yourself a spare axle seal (AL3Z-4B416-A) as you will most likely destroy the one that's installed in order to access the axle C-Clip.

Good luck !

 

Hi!

Edit: Totally editing my post from before. Why? Because as Augster pointed out, it wouldn't matter if the bolts were tightened down, and I didn't know what I was talking about (some would say I was talking out my butt )

No further explanation necessary, I think. Now I'm going to go finish my lunch of crow.


My apologies.


Liz

 

Yea, as Piggy said, it's definitely a lot of work, and although I didn't disconnect the steering shaft, I did unbolt the hydraulic steering rack from the frame (not sure if you can or need to do this with EPAS) to finagle it out of the way to R&R my front axle. It's an extremely tight fit, requiring a helper to guide and operate the floor jack, while I call out instructions using my hands to gauge clearance where I couldn't get eyes on; it's not a straight drop down show: you have drop a little, shift jack and/or axle, repeat.



For cover with drain plug, I used a Spicer:



I did have to replace one cup seal on the donor Raptor front axle (with Torsen limited slip):

 

Thank you both for your replies and photos!

Is it easy to access the drain plug on the diff cover upgrade? I thought the reason people drain and fill via the factory fill plug is because of the limited access shown in the FordTechMakuloco video. If I order the Purple Cranium cover, I don't see the need to add their fill plug option, but yes on the drain plug!

@Augster On your spicer cover, do you actually use their fill plug, or the factory fill plug?

 

There are three plugs on the Spicer cover: bottom one for drain, and two front ones for oil cooler. You actually fill the differential using the OEM fill plug.

 

It's possible the water is driving it out, mine had evidence of the grey (water infused) oil seeping out of some places, but nothing was/stayed wet after draining and refilling with oil.
What i'm saying is, service your front diff, you might find the leaking stops.

I followed this video to begin with, oil looked "great"



This is the "leak" i had.




This is the crap i got out when i vacuumed out the oil







I spent quite a long time, getting all the angles and extra crevices of oil out with the vacuum, i had no real time limit on this, yet, this problem had wrecked a couple of my diff bearings and it had to be rebuilt <50 miles later - the oil that was drained out was the same grey colour as i had gotten out originally.














I had the shop put this drain in place, the oil they got out this time, thousands of miles later, was good, so lesson being, if you're getting grey oil out, you'll need a flush-fill and drain it out again in 100 miles to get it all clean.
I do not have any active leaks from anything connected to the front diff.

 

Yeah man, the drain plug is easily accessible with a simple wrench. No need for a fill plug as the diff housing already has one.
Your first step should be to take that fill plug out to make sure it's not seized right up otherwise you'll be fu*ked when it's time to refill.

 

That's a gorgeous diff cover you got there good sir !

 

Ford also thought so, and licensed it at least for their 9.75's under the Ford Performance brand: