# Automatic transmission range switch shaft nut (NB1)

Canonical URL: https://miatatorque.com/spec/at-range-switch-shaft-nut-nb1/

Applicability: NB 1999–2000 (BP-4W, 4AT) — 2000 applicability inferred from 1999 factory evidence within the owner-approved NB1 group.

Confidence: fsm

27–43 in·lb / 3–4.9 N·m

Always confirm against your factory manual. Match every restriction and follow all stages and procedure notes. Disputed claims must not be automatically resolved. The complete record below preserves every printed unit, source claim and procedure.

```json
{
  "id": "at-range-switch-shaft-nut-nb1",
  "name": "Automatic transmission range switch shaft nut (NB1)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        1999,
        2000
      ],
      "engines": [
        "BP-4W"
      ],
      "trans": [
        "4AT"
      ],
      "note": "2000 applicability inferred from 1999 factory evidence within the owner-approved NB1 group."
    }
  ],
  "kind": "torque",
  "torque": {
    "nm": [
      3,
      4.9
    ],
    "kgfcm": [
      30,
      50
    ],
    "inlb": [
      27,
      43
    ]
  },
  "procedure": {
    "notes": "Install new packing and lock washer. Tighten nut, then bend lock-washer claws."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1999",
      "page": "05–13–13",
      "as_printed": "3.0–4.9 N·m {30–50 kgf·cm, 27–43 in·lbf}",
      "verified_years": [
        1999,
        1999
      ],
      "torque": {
        "nm": [
          3,
          4.9
        ],
        "kgfcm": [
          30,
          50
        ],
        "inlb": [
          27,
          43
        ]
      },
      "document": {
        "id": "fsm-1999",
        "tier": 1,
        "title": "1999 Mazda MX-5 Miata Workshop Manual",
        "covers": [
          {
            "gen": "NB",
            "years": [
              1999,
              2000
            ],
            "engines": [
              "BP-4W"
            ]
          }
        ],
        "url": "https://www.mellens.net/mazda/Mazda-Miata-1999-2001.pdf"
      }
    }
  ],
  "jobs": [],
  "system": "transmission",
  "component": "reaudit-1999",
  "componentName": "Additional NB1 automatic service fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/at-range-switch-shaft-nut-nb1/"
}
```