Synchro Ring and Gear Inspection

WARNING: This page is about a different variant/trim than selected.

Inspect the synchro rings for scoring, cracks, and damage (A).

Fig 1: Identifying Synchro Rings For Scoring, Cracks And Damage
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect the inside of each synchro ring (B) for wear. Inspect the teeth (C) on each synchro ring for wear (rounded off).
Inspect the teeth (A) on each synchro sleeve and the matching teeth on each gear for wear (rounded off).

Fig 2: Identifying Teeth On Synchro Sleeve And Matching Teeth On Gear For Wear
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Example of synchro sleeve teeth and gear teeth

Fig 3: Identifying Synchro Sleeve Teeth And Gear Teeth Good And Worn Condition
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect the synchro teeth on gear for scoring, cracks, and damage (A).

Fig 4: Identifying Synchro Teeth On Gear For Scoring, Cracks And Damage
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect the thrust surface (B) on each gear hub for wear.
Inspect the cone surface (C) on each gear hub for wear and roughness.
Inspect the teeth on all gears (D) for uneven wear, scoring, and cracks.
Coat the cone surface of each gear with MTF, and place its synchro ring on it. Rotate the synchro ring and make sure that it does not slip.
Measure the clearance between each gear (A) and its synchro ring (B) all around the gear. Hold the synchro ring against the gear evenly while measuring the clearance. If the clearance is less than the service limit, replace the synchro ring and gear.
Synchro Ring-to-Gear Clearance

Standard: 0.655-1.334 mm (0.02579-0.05252 in)

Service Limit: 0.4 mm (0.016 in)

Double Cone Synchro-to-Gear Clearance

Standard:
1. Outer Synchro Ring (B) to Synchro Cone (C)
  0.70-1.19 mm (0.0276-0.0469 in)
2. Synchro Cone (C) to Gear (A)
  0.50-1.04 mm (0.0197-0.0409 in)
3. Outer Synchro Ring (B) to Gear (A)
  0.95-1.68 mm (0.0374-0.0661 in)
Service Limit:
1. 0.3 mm (0.012 in)
2. 0.3 mm (0.012 in)
3. 0.6 mm (0.024 in)
  
  Fig 5: Measuring Clearance Between Gear And Synchro Ring
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Synchro ring-to-gear

Fig 6: Identifying Synchro Ring-To-Gear Clearance
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Double cone synchro-to-gear

Fig 7: Identifying Double Cone Synchro-To-Gear Clearance
Courtesy of AMERICAN HONDA MOTOR CO., INC.