# Differential drive-pinion/ring-gear backlash — minimum (NB1)

Canonical URL: https://miatatorque.com/spec/differential-ring-pinion-backlash-minimum-nb1/

Applicability: NB 1999–2000 (BP-4W) — Actual 1999 factory evidence; other years in the approved family inferred with owner approval.

Confidence: fsm

0.05 mm minimum

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": "differential-ring-pinion-backlash-minimum-nb1",
  "name": "Differential drive-pinion/ring-gear backlash — minimum (NB1)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        1999,
        2000
      ],
      "engines": [
        "BP-4W"
      ],
      "note": "Actual 1999 factory evidence; other years in the approved family inferred with owner approval."
    }
  ],
  "kind": "non-torque",
  "value_text": "0.05 mm minimum",
  "procedure": {
    "notes": "Minimum listed separately in the factory technical table. The assembly setup target remains 0.09–0.11 mm; do not set backlash to the minimum when assembling the differential. Use the full factory procedure for the cross-position inspection as well."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1999",
      "page": "03–50–1 (PDF p. 370)",
      "as_printed": "Backlash of drive pinion and ring gear\n(mm {in})\nMinimum\n0.05 {0.002}",
      "verified_years": [
        1999,
        1999
      ],
      "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": "driveshaft-differential",
  "component": "differential-inspection",
  "componentName": "Differential overhaul inspection and selection",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/differential-ring-pinion-backlash-minimum-nb1/"
}
```