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M/T Mainshaft Assembly Clearance Inspection

NOTE: If replacement is required, always replace the synchro sleeve and hub as a set.
  1. Support the bearing inner race with a socket (A), and push down on the mainshaft (B).
  1. Measure the clearance between 2nd (C) and 3rd (D) gears with a feeler gauge (E).
    • If the clearance is more than the service limit, go to Step 3 .
    • If the clearance is within the service limit, go to Step 4 .
    Standard:
    0.06−0.21 mm (0.002−0.008 in.)
    Service Limit:
    0.33 mm (0.013 in.)


  1. Measure the thickness of 3rd gear.
    • If the thickness of 3rd gear is less than the service limit, replace 3rd gear with a new one.
    • If the thickness of 3rd gear is within the service limit, replace the 3rd/4th synchro hub with a new one.
    Standard:
    27.92−27.97 mm (1.099−1.101 in.)
    Service Limit:
    27.85 mm (1.096 in.)


  1. Measure the clearance between 4th gear (A) and the distance collar (B) with a dial indicator (C). If the clearance is more than the service limit, go to Step 5 .
    Standard:
    0.06−0.19 mm (0.002−0.007 in.)
    Service Limit:
    0.31 mm (0.012 in.)


  1. Measure distance (1) on the spacer collar.
    • If distance (1) is not within the standard, replace the distance collar with a new one.
    • If distance (1) is within the standard, go to Step 6 .
    Standard:
    24.03−24.06 mm (0.946−0.947 in.)


  1. Measure the thickness of 4th gear.
    • If the thickness of 4th gear is less than the service limit, replace 4th gear with a new one.
    • If the thickness of 4th gear is within the service limit, replace the 3rd/4th synchro hub with a new one.
    Standard:
    27.02−27.07 mm (1.064−1.066 in.)
    Service Limit:
    26.65 mm (1.049 in.)


  1. Measure the clearance between the distance collar (A) and 5th gear (B) with a dial indicator (C). If the clearance is more than the service limit, go to Step 8 .
    Standard:
    0.06−0.19 mm (0.002−0.007 in.)
    Service Limit:
    0.31 mm (0.012 in.)


  1. Measure distance (2) on the distance collar.
    • If distance (2) is not within the standard, replace the distance collar with a new one.
    • If distance (2) is within the standard, go to Step 9 .
    Standard:
    24.03−24.06 mm (0.946−0.947 in.)


  1. Measure the thickness of 5th gear.
    • If the thickness of 5th gear is less than the service limit, replace 5th gear with a new one.
    • If the thickness of 5th gear is within the service limit, replace the 5th synchro hub with a new one.
    Standard:
    28.92−28.97 mm (1.139−1.141 in.)
    Service Limit:
    28.85 mm (1.136 in.)


  1. Measure the thickness of the distance collar.
    If the thickness of distance collar is not within standard, replace the distance collar with a new one.
    Standard:
    12.00−12.05 mm (0.472−0.474 in.)