Main Shaft Assemble. Chevrolet Export Chevy P42 Commercial Chassis 1999

For 1990-2009 cars

## Main Shaft Assemble NV4500

1. Clean all the parts in a suitable solvent. Air dry all the parts.

Important: Do not spin the bearings without a lubricant.

2. Lubricate the mainshaft bearings with the proper transmission lubricant.
3. Check the bearings for rough rotation.
4. Inspect the mainshaft gears for the following conditions:

• | Cracks

• | Nicks

• | Chipped gear teeth

• | High spots (small-shiny spots on the gear teeth mating surface) that could cause gear noise

5. Inspect related gear surfaces like thrust faces and bearing surface diameters.
6. Inspect the synchronizer sleeves for a sliding fit on the synchronizer hubs. The synchronizer hubs must have a force fit on the mainshaft splines.
7. Replace a synchronizer hub that does not require a force fit on the mainshaft splines.
8. Inspect the synchronizer springs and the keys for damage.
9. Inspect the synchronizer rings for excess wear.
10. Inspect the synchronizer clutching teeth for the following conditions:

• | Scuffs

• | Nicks

• | Burrs

• | Damage

11. Inspect the mainshaft drive gear clutching cones for synchronizer ring metal transfer.
12. Inspect all the gear teeth for excess wear.
13. Remove nicks and burrs with a soft stone or a crocus cloth.
14. Replace any components that are bent or show signs of excessive wear. Inspect the mating parts.
15. Inspect the bearings and the bearing surfaces for the following conditions:

• | Nicks

• | Burrs

• | Bent cages

• | Wear

• | Overheating

• | Scoring

• | Pitted condition

### Assembly Procedure

#### Tools Required

J 22828 Gear and Bearing Installer

Important: Use TRANSJEL on bearings and contact surfaces.

1. Install the 1st speed gear bearing and the 1st speed gear.
2. Install the reverse gear clutch gear and the synchronizer ring. Ensure that the synchronizer ring teeth face down toward the mainshaft shoulder.
3. Install the reverse gear clutch gear retainer ring.
4. Install the reverse bearing spacer and the bearing.
5. Install the reverse gear and the synchronizer assembly. Rotate the assembly until the gear drops into the fully seated position. If the synchronizer assembly was disassembled, the synchronizer sleeve must be reinstalled with the taper of the sleeve towards the reverse gear.
6. Install the reverse gear thrust washer.
7. Install the rear mainshaft bearing. Use a hydraulic press and the J 22828 .
8. Turn the mainshaft over.
9. Install the following parts:

9.1. | The 1st speed gear clutch gear

9.2. | The clutch gear snap ring

9.3. | The synchronizer rings

10. Install the 1st speed gear synchronizer ring retainer ring.
11. Install the 1-2 synchronizer assembly. Install the synchronizer with the taper side of the synchronizer sleeve towards 2nd speed gear.
12. Install the 1-2 synchronizer assembly retainer ring. Verify proper orientation of ring by ensuring that the letter R on the hub is up.
13. Install the 2nd speed gear synchronizer rings.
14. Install the 2nd speed gear synchronizer ring retainer ring.
15. Install the 2nd speed gear bearing.
16. Install the 2nd speed gear.
17. Install the following parts:

17.1. | The 2nd speed gear thrust washer retaining pin

17.2. | The 2nd speed gear thrust washer (Be sure the thrust washer is seated on the gear and the retaining pin.)

17.3. | The 2nd speed gear thrust washer retainer ring.

18. Install the 3rd speed gear bearing spacer and the bearing.
19. Install the 3rd speed gear and the synchronizer assembly. Hold the unit together and press on as an assembly.
20. Install the main drive gear thrust bearing.
21. Install the 4th speed gear synchronizer ring.
22. Install the 4th speed gear clutch gear.