Showing specs for all NA & NB Miatas

Reverse idler gear bushing to shaft clearance (NA6 5MT)

Standard 0.0008–0.0020 in (0.02–0.05 mm); maximum 0.006 in (0.15 mm)Standard 0.02–0.05 mm (0.0008–0.0020 in); maximum 0.15 mm (0.006 in)

Factory manualTaken from a Mazda factory workshop manual, with page citation.
Procedure

Measure clearance between the reverse idler gear bushing and shaft; inspect gear teeth for wear or cracks.

Applies to
  • NA 1990–1993 (B6, 5MT) — 1991–1993 inferred from 1990 factory evidence; actual-year verification is separate.
  • Verified in: 1990 Mazda MX-5 Miata Workshop Manual