Synchronizer Hub: Service and Repair

DISASSEMBLY
1. Place synchronizer assembly face down, then using a suitable tool, remove synchronizer spring.
2. Holding sleeve and hub assembly in place, turn assembly over to the opposite face, then remove second spring and three insert keys and slide sleeve from hub. Replace parts as necessary.

INSPECTION
1. Inspect gear teeth on synchronizer ring for chipping or excessively worn teeth, then replace as necessary.
2. Inspect synchronizer ring for wear by fitting synchronizer ring evenly to gear cone. Measure clearance between side faces of synchronizer ring and gear using feeler gauge. If clearance is less than 0.031 inch, replace synchronizer ring or gear.
3. Inspect contact between inner surface of reverse synchronizer ring and cone surface of reverse gear by applying a thin coat of Prussian blue or equivalent to surface of cone, then fit cone into ring. If pattern is poor, correct by applying compound and lapping surfaces together.
4. Inspect fiber lined blocker ring for evidence of wear, flaking, glazing and burned or missing lining material.
5. Ensure clutch sleeve sides freely on clutch hub.
6. Check synchronizer inserts (keys), inner surface of clutch sleeve and insert groove on clutch hub for wear.
7. Check synchronizer insert spring for tension.

ASSEMBLY

Synchronizer Clutch Hub To Sleeve Direction:

1. Locate indented dot reference mark on the shoulder of one face side of sleeve. Insert hub into sleeve with one of the three insert slots of hub aligned with reference mark. Ensure hub moves freely on sleeve.
2. Place hub and sleeve assembly face down, then install three insert keys into hub slots.
3. Insert one synchronizer spring into clip hole located in inner shoulder of sleeve, and place spring under protruding edge of each insert key.
4. While holding hub and sleeve together, turn assembly over and insert other spring in opposite direction of the first spring.
5. Excessive movement between hub and sleeve during sliding onto shaft will cause insert keys to pop out of hub slots.