POWER TRAINManual transmission synchronizers fail, causing erratic gear shift operation and the inability to change gears, which could result in an accident. The ND Mazda Miata Owners Group on Facebook has polled its owners and found a 10% failure rate of manual transmissions among owners in the group who required replacement of the transmission. On [XXX], at approximately 20,000 miles on the odometer, my 2022 Mazda MX-5 Miata experienced a grind from the transmission while downshifting to third gear at city speeds. I alerted Mazda North American Operations on May 30, 2024. On [XXX], the gearbox began grinding during downshifts into second gear. My car entered service at Mazda of Knoxville around June 3, 2024. Mazda of Knoxville confirmed that the vehicle required transmission replacement. Parts were not immediately available, and due to a work assignment in Des Moines, I had to drive the vehicle to Iowa. On [XXX], I noticed fourth gear began grinding during upshifts. On June 10, 2024, the vehicle entered Ramsey Mazda of Des Moines for service. Mazda North American Operations did not immediately approve repair, stating that their engineering department requested information from Mazda of Knoxville and is reviewing the claim. I am still awaiting an update. The vehicle is available for NHTSA inspection at Ramsey Mazda in Des Moines. Manual transmission failures are a serial problem for the ND-chassis Mazda MX-5 Miata since the 2016 model year, with significant failure rates reported among owners for 2016, 2017, 2022 and 2023 model years. Symptoms begin with difficulty upshifting to third gear that feels like a blocked shift gate. Grinding in the transmission soon leads to complete failure, which causes loss of throttle control and could result in an accident. My inability to select the correct gear impeded my ability to maintain safe speeds. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)