The manual gearbox is the ND's most-discussed weak point: early ND1s failed even at stock power, and a cluster of 2022-2023 ND2 cars developed 3rd/4th-gear synchro trouble around 4k-7.5k miles that Mazda replaced entirely under warranty. The replacement units are reported trouble-free.
Manual transmission synchro / gear failures (early ND1 and 2022-2023 ND2)
Mazda MX-5 Miata (ND) · mechanical