Isuzu AA-6HK1T, Workshop Manual

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ENGINE MECHANICAL 6A–67
1. Remove the flywheel housing.
Refer to “Flywheel Housing Removal” in this manual.
2. Measure the idler gear backlash.
1. Set a dial indicator to the idler gear.
Hold both the gear to be checked and the
adjoining gear stationary.
Move the gear to be checked as far as possible
both to the right and to the left.
Take the dial indicator reading.
If the measured value exceeds the specified limit,
the idler gear must be replaced.
Idler Gear Backlash
Standard : 0.10 – 0.17 mm (0.0039 - 0.0067 in)
Limit : 0.30 mm (0. 12 in)
3. Measure the gear end play.
Insert a feeler gauge between the idler gear and the
thrust collar to measure the gap and determine the
idler gear end play.
If the measured value exceeds the specified limit, the
idler gear must be replaced.
Idler Gear End Play
Gear A and B
Standard : 0.08 - 0.14 mm (0.0032 - 0.0055 in)
Limit : 0.20 mm (0.008 in)
Gear C
Standard : 0.07 - 0.135 mm (0.0027 - 0.0053 in)
Limit : 0.20 mm (0.008 in)
4. Remove the idler gear A, shaft, and thrust collar.
Inspect the idler gear for damage or wear.
Inspect the thrust collar for wear.
5. Remove the oil pump from the cylinder block.
Inspect the gear shaft for abnormal play.
Clean the fitting surfaces of the oil pump and remove
the sealant residue.
6. Remove the idler gear B, shaft, and thrust collar.
Inspect the idler gear for damage or wear.
Inspect the shaft and thrust collar for wear.
Clean the front surfaces of the cylinder block and
remove the sealant residue.
Inspection and Repair
Make the necessary adjustments, repairs, and part
replacements if excessive wear or damage is
discovered during inspection.
1. Use a micrometer to measure the idler gear shaft
outside diameter.
If the measured value is less than the specified limit,
the idler gear shaft and/or shaft must be replaced.
Idler gear shaft outside diameter
Shaft A
Standard: 49.950 – 49.975 mm (1.9665 – 1.9675 in)
Limit: 49.90 mm (1.9646 in)
Shaft B and C
Standard: 29.959 – 29.980 mm (1.1795 – 1.1803 in)
Limit: 29.9 mm (1.1772 in)
014EY00052
014EY00053