I just imported a used 2006 Lincoln Navigator Ultimate 4x4 to Germany. Parts are not an issue and several selected authorized "US Ford" dealers can order parts and perform maintenance. Two issues I would like to ask you for your expertise.
Speed governor: the 300hp are adequate and on a free autobahn I would cruise at 70 to 80 mph. However, if the autobahn is packed it is helpful to maintain the same pace as the rest on the left lane to avoid getting pushed into the right lane between trucks traveling at 55mph. For short stretches the average speed raises to 110 to 120 mph. With the Navigator, the speed governor kicking in at about a 100mph is very annoying. The truck seems to be capable of much higher speeds and it is not my intent to travel for extended stretches at these speeds, but it would be less painful to maintain the pace on the left lane until there is space on the right to merge in without getting trapped behind a truck. Question: What is the easiest way to disable the governor? Voiding warranty is not an issue, as it will not be recognized for a vehicle registered in Germany anyhow. Can this be done at a dealership and if so, how? If not, what would be the simplest programming tool (do not want to increase horsepower or mess with any other settings)?
Maintenance: I understand there is a major scheduled maintenance every 15k miles. However, there are services in between identified in the service manual. Here a service every 5,000 miles consists of an oil change and a recommended multi-point inspection. Question: Does engine oil have to be changed every 5k miles or 15k miles. 5k would seem to me ridiculously low. Even more oil demanding Diesels here heave oil change intervals twice as long?
As far as kicking up the powertrain control module's speed limitation programming is concerned, it's not gonna happen with Ford's approval, but you can accomplish the task with Hypertech's Max Energy Power Programmer. This box can do a lot more than raise the speed limit -- up the rev limiter, optimize for 87 or 93 octane fuel, calibrate the speedo for aftermarket tire sizes and gear ratios, and so on -- but you can use only the tools you desire without affecting other OEM parameters.
Important note: manufacturers may have speed limitations set to prevent the vehicle from traveling above the maximum speed ratings of the original tires for prolonged periods of time. With that said, check the speed rating of your tires and upgrade accordingly to the match the modified speed limitations. On a personal note, banking turns at a buck-twenty in a full-size SUV is not a smart way to travel, regardless of your schedule.
As far as service, I suggest sticking to the manufacturer's specified oil change intervals, regardless of what the Joneses are doing. The 5k recommendation on your Navigator is the upper end for normal driving conditions. In more severe conditions, prolonged idling and lots of dust, the interval is 3k. My patented advice is adhering to the severe schedule, regardless, if you plan on keeping the car or truck for a long time.