Disassembly
Special Tool(s)
All vehicles
1. WARNING: Wear protective eye wear whenever using compressed air.
Clean the transmission exterior with solvent, and dry with compressed air.
2. WARNING: Wear protective eye wear whenever using compressed air.
Clean all parts removed with solvent, and dry with compressed air.
3. Remove the clutch release lever and the clutch release hub and bearing.
4. Position the transmission on the floor with the output flange pointing upward.
4x2 vehicles
5. Using the special tools, remove the pinion flange.
All vehicles
6. Remove the 19 bolts.
7. NOTE: Use a 1/8 inch center punch to create a pilot hole in the plug before installing the tool. Using the Jet Plug Remover to make the pilot hole will damage the tool.
Using the special tool, remove the detent plugs and shift detent springs. Discard the detent plugs.
^ Lightly thread in the Jet Plug Remover so as not to damage the springs.
8. Remove the main shift detent.
9. Separate the main shift detent from the detent plunger.
^ Inspect the detent plunger for wear or damage. Install a new dent plunger as necessary.
10. Remove the extension housing from the intermediate housing.
^ Using a soft-faced hammer, tap the extension housing lightly to break the gasket seal.
11. Remove the intermediate housing to case bolts.
^ Early production vehicles will have three bolts.
12. Using a suitable lifting device, a suitable chain and two S-hooks, lift the intermediate housing and gear assembly out of the main case.
^ Place the S-hooks in the intermediate housing where the two bolts were removed.
^ Place a protective cover or rag around the chain. This will ensure the low and reverse gears are not damaged during removal.
^ Lift the transmission 1 inch (25 mm) off the ground. Using a soft faced hammer, lightly tap the main housing to break the gasket seal.
13. Position the intermediate housing and gear assembly on the special tool.
^ Securely fasten the holding plate to a sturdy work bench.
14. Remove the low/reverse/fifth gear main shift rail driver.
1 Remove the two roll pins.
^ Use a hammer and punch or an air hammer and roll pin remover.
2 Remove the main shift rail driver.
15. Remove the two first/second and third/fourth rail driver roll pins.
^ Use a hammer and punch or an air hammer and roll pin remover to remove.
16. Remove the first/second and third/fourth rail driver and the main shift rail.
1 Remove the first/second and third/fourth rail driver.
^ Rotate the rail driver counterclockwise and pull outward to remove.
2 Remove the main shift rail.
17. Align the interlock plate into second gear position, engage second gear, then remove the two fifth gear shift fork roll pins.
^ Use a hammer and punch or an air hammer and roll pin remover to remove.
18. Remove the fifth gear shift fork and shift rail.
^ Align the interlock plate into the fifth gear position. Remove the shift rail by tapping the shift fork with a soft faced hammer while pulling up on the shift rail.
19. Remove the low and reverse gear shift fork roll pin.
^ Use a hammer and punch or an air hammer and roll pin remover to remove.
20. Remove the low/reverse gear shift fork and shift rail.
^ Align the interlock plate into the low/reverse gear position. Remove the shift rail by tapping the shift fork with a soft faced hammer while pulling up on the shift rail and fork.
21. Remove the shift rail detents, if necessary.
^ The shift rail detents can be difficult to remove. Using a heat gun, apply heat to the intermediate plate to ease removal.
22. On 4-wheel drive vehicles, remove and discard the snap ring.
23. Using the special tools, remove the mainshaft rear bearing, the output bearing thrust washer, mainshaft low gear, the mainshaft low gear bushing, the synchronizer assembly (low and reverse) and the mainshaft reverse gear.
24. Remove the mainshaft rear bearing and the output bearing thrust washer from the low and reverse assembly.
^ Inspect the bearing for wear or damage. Install a new bearing as necessary.
^ Always install new bearings and cups as a set. Do not install one without the other.
25. Remove the mainshaft needle bearings.
^ Inspect the bearings for wear or damage. Install new bearings as necessary.
26. Remove the low gear from the low and reverse synchronizer assembly.
^ Inspect the low and reverse gears for wear or damage. Install new gears as necessary.
27. Disassemble the low and reverse synchronizer assembly.
^ Inspect the components for wear or damage. Inspect the internal surface of the synchronizer rings for a contact pattern. The contact pattern should be the same on the entire internal circumference of the ring.
28. Check the clearance between the synchronizer ring and the gear.
1 Place the synchronizer ring onto the synchronizer sliding sleeve. Position the synchronizer ring on the gear.
2 Insert a feeler gauge and measure the clearance, while applying pressure and rotating the synchronizer ring. The clearance should be the same around the entire circumference.
^ Place the feeler gauge between the ring and gear. The ring has a raised section, inserting the feeler gauge past the teeth will give a incorrect reading.
^ If the clearance is less than 1.0 mm (0.40 inch) for low or reverse gear, install a new synchronizer assembly, low gear or reverse gear to obtain correct specification.
29. Remove the mainshaft needle bearing.
30. Remove and discard the snap ring.
31. Remove the countershaft rear thrust washer.
32. Remove fifth gear.
33. Remove the countershaft needle bearing.
34. Remove the interlock plate bolts.
35. NOTE: Make sure the shift rails are not binding while pulling up on the intermediate housing.
Using the special tools, remove the countershaft bushing, the countershaft fifth gear synchronizer assembly and the intermediate housing.
^ When installing the center plate Legs, position them opposing one another.
^ Inspect the countershaft fifth gear synchronizer, countershaft bushing and the intermediate plate for wear or damage. Install new components as necessary.
36. CAUTION: To prevent damage, do not heat the mainshaft rear bearing, the countershaft or mainshaft rear thrust washer, the mainshaft bushing or the countershaft bushing higher than 150°C (300°F) maximum.
NOTE: Make sure the components are heated to 150°C (300°F) for reassembly.
New or original components should be heated in advance of the assembly procedure. Heating will ease the assembly process. Place the mainshaft rear bearing, the countershaft rear thrust washer, the countershaft bushing, the rear mainshaft bearing, the and the mainshaft low gear bushing into the Gear/Bearing Heater.
37. Remove the interlock plate, the first/second and third/fourth shift fork and shift rail assemblies.
38. Inspect all the shift fork pads and centers for wear or damage. Install new shift forks as necessary.
39. CAUTION: To prevent damage, do not heat the bearings higher than 150°C (300°F) maximum.
Inspect the mainshaft middle bearing, the countershaft middle bearing and the bearing cups in the intermediate housing for wear or damage. Install new components as necessary.
^ Always install new bearings and cups as a set. Do not install one without the other.
^ The bearings should be heated to install. Place the bearings in the Gear/Bearing Heater.
40. Remove the countershaft rear bearing spacer.
41. Remove the countershaft from the Gear Pack Assembly Fixture and set it aside.