While going approximately 55 mph, the speedometer dropped out to zero. After a moment, the transmission dropped into first gear (it felt like) and the rear tires made loud screeching noises as if they locked up for about one second. The speedometer remained at zero and the whole thing happened again in a few seconds. I was barely able to maintain directional control and if this condition would have persisted for longer, directional control would probably have been impossible to maintain. This happened on an interstate in a middle lane with a lot of traffic and within a construction zone with no good option for maneuvering. Upon further research, I found that this has been a common problem with the Ford 6R80 transmission (which is in this vehicle) and that at least one recall has been sent out, but for a different model vehicle (the Ford F-150, I believe). I cannot believe that the same known defect in a transmission which just happens to be in a different model vehicle is a acceptable situation for safety in any case. I called the Lincoln factory hotline and they could not help me in any way. I was told to go to a dealer. I went to a dealer and they couldn't help me, either. All for a known issue with that transmission. The dealer told me to have it fixed at my own cost, even though they knew of this problem. I have since had it fixed, but I have two questions: 1. How can a manufacturer be allowed to leave a known safety hazard to persist and 2. How can the NHTSA ignore this problem?

- Rogers, MN, USA

The contact owns a 2016 Lincoln Navigator. The contact stated that while driving at highway speeds, the transmission inadvertently down shifted and nearly caused the contact to lose control of the vehicle. Additionally, the speedometer gauges went to zero and the service wrench warning light was displayed. The vehicle was taken to the local dealer who diagnosed that the transmission molded lead frame was faulty and needed to be replaced. The contact was concerned that the transmission control module was faulty and needed to be serviced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 69,000.

- Vancouver, WA, USA