Main Shaft Assembly for Single-Range: Inspection

Disassembled parts should be washed with cleaning solvent first, then inspected carefully.

1. Bearing

   Replace the bearings in the following cases.

   • When the bearing balls, outer races and inner races are broken or rusty.
   • When the bearing is worn.
   • When the bearings fail to turn smoothly or emit noise in rotation after gear oil lubrication.
   • When bearing has other defects.
2. Bushing (each gear)

   Replace the bushing in following cases.

   • When the sliding surface is damaged or abnormally worn.
   • When the inner wall is abnormally worn.
3. Gear

   Replace gears in the following cases.

   • Replace the gear with new part if its tooth surfaces are broken, damaged or excessively worn.
   • Correct or replace if the cone that contacts the baulk ring is rough or damaged.
   • Repair or replace if the inner surface or end face is damaged.
4. Baulk ring

   Replace the baulk ring in the following cases.

   • When the inner surface or end face is damaged.
   • When the ring inner surface is abnormally or partially worn down.
   • When the contact surface of the synchronizer ring insert section is cracked or abnormally worn.
   • If the gap between the end faces of the ring and the gear splined part is excessively small, check the clearance (A) while pressing the ring against the cone.

     Clearance (A): 

     0.5 mm (0.020 in) or more 

     Fig 1: Identifying Clearance Between End Faces Of Ring And Gear Splined Part

     Courtesy of SUBARU OF AMERICA, INC.
   • Apply gear oil to the cone of the gear and while press-fitting the synchronizer ring, check there is no rotation in the circumferential direction.
     Fig 2: Checking Synchronizer Ring (Circumferential Rotation)

     Courtesy of SUBARU OF AMERICA, INC.
5. Shifting insert

   Replace the shifting insert if there is deformation, excessive wear on the ball section or any defectiveness.

   Fig 3: Identifying Shifting Insert

   Courtesy of SUBARU OF AMERICA, INC.
6. Coupling sleeve and synchronizer hub
   • Check the slipping condition of the coupling sleeve.
   • Check the splines on the coupling sleeve and synchronizer hub for wear.
7. Oil seal

   Replace the oil seal if the lip is deformed, hardened, worn or defective in any way.

8. Gearshift mechanism

   Repair or replace the gearshift mechanism if excessively worn, bent or defective in any way.