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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 an appropriate sized 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:
    0.30 mm (0.012 in.)


  1. Measure the thickness of 3rd gear.
    • If the thickness is less than the service limit, replace 3rd gear.
    • If the thickness is within the service limit, replace the 3rd/4th synchro hub and 3rd/4th synchro sleeve as a set.
    Standard:
    27.02−27.07 mm (1.064−1.066 in.)
    Service Limit:
    26.95 mm (1.061 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:
    0.28 mm (0.011 in.)


  1. Measure distance (1) on the distance 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:
    22.53−22.56 mm (0.887−0.888 in.)


  1. Measure the thickness of 4th gear.
    • If the thickness is less than the service limit, replace 4th gear.
    • If the thickness is within the service limit, replace the 3rd/4th synchro hub and 3rd/4th synchro sleeve as a set.
    Standard:
    25.52−25.57 mm (1.005−1.007 in.)
    Service Limit:
    25.45 mm (1.002 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:
    0.06−0.14 mm (0.002−0.006 in.)
    Service Limit:
    0.23 mm (0.009 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:
    22.53−22.56 mm (0.887−0.888 in.)


  1. Measure the thickness of 5th gear.
    • If the thickness is less than the service limit, replace 5th gear.
    • If the thickness is within the service limit, replace the 5th/6th synchro hub and 5th/6th synchro sleeve as a set.
    Standard:
    22.42−22.47 mm (0.883−0.885 in.)
    Service Limit:
    22.35 mm (0.880 in.)


  1. Measure the clearance between the 6th gear (A) and angular ball bearing (B) with a feeler gauge (C). If the clearance is more than the service limit, go to Step 11 .
    Standard:
    0.06−0.16 mm (0.002−0.006 in.)
    Service Limit:
    0.25 mm (0.010 in.)


  1. Measure the thickness of the distance collar.
    • If the thickness is not within the standard, replace the distance collar.
    • If the thickness is within the standard, go to Step 12 .
    Standard:
    24.03−24.08 mm (0.946−0.948 in.)


  1. Measure the thickness of 6th gear.
    • If the thickness is less than the service limit, replace 6th gear.
    • If the thickness is within the service limit, replace the 5th/6th synchro hub and 5th/6th synchro sleeve as a set.
    Standard:
    23.92−23.97 mm (0.942−0.944 in.)
    Service Limit:
    23.85 mm (0.939 in.)