Yea right! When/If the diff fails at 62k miles due to damage caused by this problem, Ford is highly likely to deny the warranty repair claim. Ford has a well-known history of doing this sort of thing. They are famous for denying legitimate warranty claims on known defective components if the vehicle is even 15 days or 100 miles out of warranty, for example... diff failures on 2002-2004 Explorers with IRS, or timing chain failures on SOHC 4.0L V/6 engines, I personally saw this sort of thing many times. Unless Ford gives you a warranty extension in writing, something that other manufacturers occasionally do, I don't trust them.
Most automakers will deny warranty repair after the warranty
expires, not just Ford. You hear stories of "good will" repairs, but those types of repairs will be less likely on really pricey jobs. It definitely sucks when a pricey component fails just outside of the warranty period, but automakers cannot warranty products forever. That's why the extended warranty companies and programs exist. They feed off of people's fear of having expensive repairs and then sell people expensive coverage (that many times is also denied when claims are submitted.) That's just car ownership. I would never expect an automaker to cover something outside of the warranty period, unless it was a safety related recall.
Having a problem documented before the warranty period is over also does not guarantee that it will be fixed for free after the warranty ends. It gives you ammunition to approach the manufacturer about a "good will" repair of a recurring problem, but does not obligate the manufacturer to actually cover it outside of warranty.
I have personally had automakers refuse to fix problems on new cars while under warranty. In the early 90's I had a Plymouth Sundance Duster. The "stainless steel" exhaust needed replacement after only 12 months. Not covered under warranty due to the corrosion supposedly being "environmental". When I questioned why a 12mo old car would need a whole new exhaust, the dealer agreed to cover labor if I paid for the parts. Only other issues I had while I owned it were a bad radio, a loose squirrel cage around the blower motor, and a bad coil. All covered under warranty.
In the late 90's I bought a new Pontiac Grand Prix. It had an intermittent no-start condition. I called the dealer to schedule an appointment, and they asked if I had a service engine light. I said no. They literally said "We don't want to see it unless there is a light. Until then, there is nothing we can do." The car developed other major electrical problems but never threw a code, so I traded it after only owning it for 6 months.
I also had a Ford Explorer that Ford spent thousands under warranty repairing a structural/frame deficiency from the factory (missed welds during assembly.) Got it back after several weeks only to have a brake caliper seize. The caliper was replaced, then seized again 1,000 miles later. It was replaced again with the warning that if it seized again it would no longer be covered under warranty and I would have to pay out of pocket. The vehicle only had 17,000 miles on it at the time. Got rid of the Explorer a few months later when the same brake started having issues again.
Chevy denied turning the warped rotors on my Impala under warranty, even though I had a copy of a TSB that stated that turning rotors was covered under the 3yr/36K mile warranty at the time. Dealer acknowledged the legitimacy of the TSB but refused to warranty the work despite what the TSB stated.
I purchased a new Hyundai that had a scenario where the drive belt would squeal and the battery light on the dash would come in when driving in heavy rain. During the 30,000 mile service (car had a 5yr/60K mile warranty, and a 10yr/100K mile powertrain warranty) I explained the situation to the dealer. They said it wouldn't be covered under warranty. When I asked why, they said since it was a possible drive belt issue that is a wear item and not covered. They looked at it, said the belt was fine and the light was "normal", and not to worry about it. Car did that for the whole 5 years I owned it. Traded the car when it started using (not burning or leaking) 1qt of oil every 800 miles.