Countershaft and Reverse Idle Gear Inspection

Countershaft and Reverse Idle Gear Inspection
Reference: Manual Transmission Assembly Dismounting and Remounting: H27 Engine Model
Reference: Manual Transmission Unit Disassembly: H27 Engine Model
Reference: Countershaft and Reverse Idle Gear Disassembly and Assembly: H27 Engine Model





^ Using micrometer, check diameter of countershaft as shown. If measured valve is out of specification, replace it.
Countershaft diameter (standard)
"a": 29.984 - 30.000 mm (1.1805 - 1.1811 inch)
"b": 34.000 - 34.015 mm (1.3386 - 1.3392 inch)





^ Measure width "a" of 5th gear shift fork and groove width "b" of 5th gear synchronizer sleeve and then calculate clearance "c" as follows:
Clearance "c" = "b" - "a"
If clearance exceeds limit, replace fork and sleeve.
Clearance "c" between fork and sleeve
Standard: 0.26 - 0.84 mm (0.010 - 0.033 inch)
Limit: 1.0 mm (0.039 inch)
Check the following clearance and gear tooth.
^ Between synchronizer ring and synchronizer dog.





^ Between chamfered tooth of synchronizer dog and synchronizer ring. If clearance exceed limit, replace with new one.
Clearance between synchronizer ring and synchronizer dog (countershaft)
Standard: 0.68 - 1.32 mm (0.027 - 0.052 inch)
Service limit: 0.5 mm (0.020 inch)





^ Using cylinder gauge (1), check inside diameter of countershaft 5th gear (2). If measured value exceeds specification, replace countershaft 5th gear.
Countershaft 5th gear diameter
Standard: 38.015 - 38.040 mm (1.4967 - 1.4976 inch)





^ Check oil clearance between reverse idle gear (2) and shaft (1) measuring inside diameter ("a") of gear and diameter ("b") of shaft and calculate as follows:
Clearance "c" = "b" - "a"
If clearance exceeds limit, replace gear and shaft.
Oil clearance "c" between reverse idle gear and shaft
Standard: 0.040 - 0.082 mm (0.0016 - 0.0032 inch)
Limit: 0.13 mm (0.005 inch)





^ Check clearance between reverse idle gear (2) and shoe (1) of reverse gear shift arm. If clearance exceeds limit, replace shoe.
Clearance between reverse idle gear and shoe
Standard: 0.05 mm - 0.35 mm (0.002 - 0.014 inch)
Limit: 0.5 mm (0.020 inch)