Important: Do not disassemble the countershaft. Individual components of the countershaft are not serviced. A damaged or worn countershaft must be replaced as a complete assembly.

1. Clean the countershaft in a suitable cleaning solvent. Air dry the countershaft.
2. Inspect the countershaft for cracks.
3. Replace a cracked countershaft.
4. Inspect the countershaft gears for the following conditions:

•	Scuffed gear teeth

•	Nicked gear teeth

•	Burred gear teeth

•	Broken gear teeth

•	High spots (Small shiny spots on the gear teeth mating surfaces) that could cause gear noise

5. Lubricate the countershaft bearings with GM P/N 12345349 Syncromesh Transmission Fluid (or equivalent).
6. Replace the bearing assembly if any of the following conditions exist:

•	Roughness of rotation

•

Burrs

•	Pitted condition

7. Replace the bearing race and inspect the mating parts If the following conditions exist:

•

Scoring

•

Wear

•	Discoloration from overheating