NHTSA Complaint #11716941 — 2021 LINCOLN NAVIGATOR

While driving, the vehicle repeatedly hesitated during gear changes, lost power, and then abruptly jerked back into gear. This occurred intermittently for over a month without any warning messages, creating unpredictable and unsafe driving conditions. As the issue worsened, the vehicle began losing power more frequently. The most serious event occurred at highway speed, where the vehicle suddenly lost propulsion in the middle of active traffic, nearly causing a stall. This created an immediate safety hazard for myself and surrounding drivers. After several seconds, the vehicle violently re-engaged into gear and surged forward. Only at this point did the vehicle display a warning: “Powertrain Malfunction / Reduced Power.” I scanned the vehicle and retrieved DTC P0734 – Gear 4 Incorrect Ratio, a code associated with internal transmission faults. A dealership inspected the vehicle and reported that the CDF drum had failed. They stated they could not guarantee that replacing the drum would resolve all issues and provided two estimates: $5,600 for a partial internal repair/$8,700 for full transmission replacement. The 10R80 transmission has a documented history of failures, including harsh shifting, slipping, unexpected gear disengagement, and internal component defects. These issues are addressed in multiple Ford Technical Service Bulletins involving P0734, harsh/failed shifts, and failures related to the CDF clutch cylinder/drum. Many vehicles of the same make and model are covered under related recalls or service actions for similar problems; however, my VIN is not included, and Lincoln declined to honor the existing recall. This defect presents a serious safety risk due to: Sudden loss of power while driving, including at highway speeds, Unpredictable re-engagement and violent surging, Loss of propulsion without warning, leading to near-stall conditions. This powertrain malfunction is a known, unsafe, repeat issue among these vehicles equipped w/this transmission.