Rear pinion seal leak

[cdlamb]

I own a 2018 F150 with 73000 kilometers, (about 45,000 miles).

I noticed that the rear diff is leaking from the pinion seal.

I removed the plug to check the level, & might be a little low, maybe 1/2 inch below threads, but there was also a good coating of fine metallic sludge stuck to the magnet. I cleaned it off, & going to purchase a jug to top it off, & book it in to have it looked at (warranty should cover it)

Thinking I might send an oil analysis in case something is failing internally.

This truck has the 3.55 ELECTRONIC LOCK RR AXLE. It has been used a few times but very rarely gets used. Have there been any reports of failures on the Ford locking diffs?

I did check the vent hose and it was clear.

 

[nascarnation]

That's not a major operation like changing the rear main seal in an engine, so it might be worthwhile to swap it out, especially if warranty is paying

 

[Lubener]

Unless there is a lot of metal shavings stuck on the plug, a dark sludgy coating on the plug is normal. I have to wipe the plug clean everytime I do a gear oil check. A half inch below the plug is nothing to be concerned about and probably was originally filled to about 3/8 inch below the plug anyway.
I have a Mercury which was under warranty at the time with a small pinion leak. I went from having a nice quiet differential to a whiney one. The dealer was never able to completely silence the gear whine. Now, I should have just lived with the small weepage. Even the dealer can screw up something.

 

[cdlamb]

Yes, I was just going to purchase a liter of oil & top it off, keeping an eye on it.

I checked the oil when it was new at the first engine oil change, & yes, they are filled to 1/4 inch below threads.

The oil came to $47.00/ liter.

I just decided to book it in for service.

Warranty will cover the top off, & if I have problems down the road after warranty period expires, it should still be covered as a pre-existing condition.

 

[dlundblad]

The metal sludge is very normal especially on new gears. They’re just breaking in and meshing together. Top it off and drive on.