Mainshaft and Synchronizers. Chevrolet Export Chevy P42 Commercial Chassis 2000

For 1990-2009 cars

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

Important: Do not spin the bearings without a lubricant.

2. Lubricate the mainshaft bearings with Synthetic Manual Transmission Fluid GM P/N 12346190.
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 such as thrust faces and bearing surface diameters.
6. Inspect the mainshaft bearing surfaces for wear or damage.
7. Inspect the synchronizer sleeves for a sliding fit on the synchronizer hubs. The 3rd and 4th gear synchronizer hub must have a force fit on the mainshaft splines.
8. Replace the 3rd and 4th gear synchronizer hub that does not require a force fit on the mainshaft splines.
9. Inspect the synchronizer springs and the struts for damage.
10. Inspect the synchronizer rings for excess wear.
11. Inspect the synchronizer clutching teeth for the following conditions:

• | Scuffs

• | Nicks

• | Burrs

• | Damage

12. Measure the cap between the verical faces of the blocking ring teeth and the synchronizer clutch gear as follows:

12.1. | Assemble the correct blocking ring with the synchronizer clutch gear.

12.2. | The blocking ring must be fully seated on the gear.

12.3. | Use a feeler gauge to measure the gear gap.

• | 1st gear (between the hub and outer ring) 1.37-0.31 mm (0.054-0.012 in)

• | 2nd gear 2.16-1.14 mm (0.085-0.045 in)

• | 3rd gear 1.73-0.76 mm (0.068-0.030 in)

• | 4th gear 2.10-1.19 mm (0.079-0.047 in)

• | Overdrive gear 1.83-1.07 mm (0.072-0.042 in)

• | Reverse gear 2.24-1.47 mm (0.088-0.058 in)

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

• | Nicks

• | Burrs

• | Bent cages

• | Wear

• | Overheating

• | Scoring

• | Pitted condition