GM Service Manual Online
For 1990-2009 cars only

    Object Number: 412471  Size: SH
  1. Clean the balance shafts in solvent.
  2. Inspect the bearing surfaces on the balance shafts for scoring or unusual wear.
  3. Inspect the balance shaft drive sprockets for wear, damage, or missing teeth.
  4. Measure the rear bearing journals on the balance shafts, the journals should be 36.723-36.743 mm (1.4458-1.4466 in) in diameter.
  5. Measure the front bearing journals on the balance shafts, the front bearing journals should be 20.020-20.000 mm (0.7881-0.7874 in) in diameter.
  6. When the balance shafts have been installed in the engine block, check for smooth rotation, sticking, binding, or roughness.