Your transmission is in a default "limp-in" mode designed to get you home or to a shop, minimizing damage to the transmission while doing so. That there's a transfer case diagnostic code indicates that there's a problem in the transfer case control system. Get it checked by a Lincoln/Ford specialist or a transmission shop.
If you want to find a Lincoln specialist, here's our directory link for you:
https://repairpal.com/lincoln-repair-in-jamaica-new-york
RepairPal Certified shops can diagnose and repair your 2000 Lincoln Navigator. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.