the jack would be covered under its own warranty, even if you don't have the FR warranty.
just like the oven, a/c, awning, converter, fridge/freezer, stove, roof membrane, tires, axles, furnace and so on.
but RV manufacturers only warranty to the original purchaser. none of them allows for warranties to transfer.
that's why the only 3rd party warranty i'd buy, would be on a used RV.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC