# Differential side-gear thrust-washer selection (NA6)

Canonical URL: https://miatatorque.com/spec/differential-side-gear-thrust-washer-selection-na6/

Applicability: NA 1990–1993 (B6, open) — Actual 1990 factory evidence; other years in the approved family inferred with owner approval.

Confidence: fsm

Mark 0: 1.95–2.00 mm; mark 1: 2.05–2.10 mm; mark 2: 2.15–2.20 mm

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-side-gear-thrust-washer-selection-na6",
  "name": "Differential side-gear thrust-washer selection (NA6)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "diff": [
        "open"
      ],
      "note": "Actual 1990 factory evidence; other years in the approved family inferred with owner approval."
    }
  ],
  "kind": "non-torque",
  "value_text": "Mark 0: 1.95–2.00 mm; mark 1: 2.05–2.10 mm; mark 2: 2.15–2.20 mm",
  "procedure": {
    "notes": "Open differential only. Select the thrust washers required to achieve side-gear/pinion-gear backlash of 0–0.1 mm. Mark numbers identify thickness choices; they are not backlash measurements. Follow the full factory differential reassembly procedure and secure the pinion-shaft knock pin as specified."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "M–40 (PDF p. 423)",
      "as_printed": "Thrust washer thickness:\nIdentification mark   Thickness\n0   1.95—2.00mm (0.0768—0.0787 in)\n1   2.05—2.10mm (0.0807—0.0827 in)\n2   2.15—2.20mm (0.0846—0.0866 in)",
      "verified_years": [
        1990,
        1990
      ],
      "document": {
        "id": "fsm-1990",
        "tier": 1,
        "title": "1990 Mazda MX-5 Miata Workshop Manual",
        "part_number": "1193-10-89C",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1990,
              1990
            ],
            "engines": [
              "B6"
            ]
          }
        ],
        "url": "https://archive.org/details/1990-mazda-mx-5-miata-workshop-manual_202411"
      }
    }
  ],
  "jobs": [],
  "system": "driveshaft-differential",
  "component": "differential-inspection",
  "componentName": "Differential overhaul inspection and selection",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/differential-side-gear-thrust-washer-selection-na6/"
}
```