Help With Front Diff Leak

[Tone]

'21 3.5 EB, 37K.

Noted a small leak. Took to dealer who diagnosed as front differential leak. They took the cover off, siliconed and filled with oil.

When picking it up, noted a small amount of oil underneath which I accepted as slop from the change. At home, extensively wiped the area clean and put a piece of cardboard underneath. Checked four hours later and no leak.

Came out this morning to find the leak worse (pix). Taking the vehicle back to dealer on Friday.

Odd that there was a delay in leaking.

Anyone experience this? What was the issue and how was it remediated?

Thanks for your help.

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[Gros Ventre]

The time delay implies to me that they did not seal around the bolt holes for the cover.

 

[Tone]

Possible.

I'm wondering if the truck — on a slight down angle — dripped more slop I did not reach higher up. That would explain why no drips fro hours as the oil slowly made its way down to drip.

Cleaned some more and put a clean piece of cardboard under. So far so good.

 

[TheGoatman]

I changed the fluid without dropping the diff or moving the rack. I was successful but was ready for it to leak based on access. A lot of the top is done blind.
a pro to do this on a paid job, imo, is a real hack job.

 

[bp1954fromca]

'21 3.5 EB, 37K.

Noted a small leak. Took to dealer who diagnosed as front differential leak. They took the cover off, siliconed and filled with oil.

When picking it up, noted a small amount of oil underneath which I accepted as slop from the change. At home, extensively wiped the area clean and put a piece of cardboard underneath. Checked four hours later and no leak.

Came out this morning to find the leak worse (pix). Taking the vehicle back to dealer on Friday.

Odd that there was a delay in leaking.

Anyone experience this? What was the issue and how was it remediated?

Thanks for your help.

Are you sure the original leak was the cover? Mine had a small leak and it was the pinion seal. Over time the underside of the diff was wet from the cover to the pinion. I would wipe it off and after next drive check to see where leak actually is.

 

[Tone]

The envelope, please ... cracked front diff housing.

Truck at dealer for about two weeks..

 

[DNazzy’s2025]

Had my truck for about 3 months. Noticed leak where the CV shaft enters the axle… assuming this is a pinion leak? I don’t see any fluid near the differential housing.

 

[Tone]

It's a crack in the front diff.

 

[JKinPA]

Mine did the same. Dealer replaced the front dif, took a day after they got the part, which was three days. My leak was not as severe and I was able to drive it. They added some fluid and said it was good unless it got worse. Kept it 2H.

 

[DNazzy’s2025]

The entire differential had to be replaced?

 

[JKinPA]

That’s what they recommended and it was under warranty so I wasn’t arguing

 

[Tone]

I asked, they strongly recommended not to drive mine. Swapping entire diff.

Leak is very heavy.

 

[JKinPA]

I asked, they strongly recommended not to drive mine. Swapping entire diff.

Leak is very heavy.

Mine wasn’t horrible, a few drops when it was parked but I kept an eye on it. My local Ford has a great group in the shop. They have treated me well.

 

[Tone]

There's lots of well-founded bitching about dealerships failing to provide good service. Rarer are posts about incredible service. This is one.

Dealership stated it would take two weeks to change the front diff dropped off on Friday and parts ordered then. Imagine my surprise when I received a call Tuesday morning the work was done. It seems miraculous for the amount of work necessary to remediate this problem.

Thank you Steet-Ponte Ford.

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