GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Aurora 🢒 Driveline/Axle 🢒 Transfer Case - NVG 233-NP1 (Two Speed Selectable) 🢒 Transfer Case Cleaning and Inspection
  1. Clean the following components:
    2. • The bearings
    • Remove all of the old lubricant and any dirt.
    • The shafts
    • The sprockets
    • The chain
    • The oil feed ports and channels in each case half
    • Apply compressed air to each oil feed port and channel in order to remove any obstructions or cleaning solvent residue.
    • All of the mating and sealing surfaces.
  2. Inspect the bearings and the thrust washers for the following conditions:
    3. • Spalling
    • Brinneling
    • Corrosion
  3. Inspect the gear teeth for the following conditions:
    4. • Excessive wear or damage
    • Spalling
    • Cracks
    • Corrosion
  4. Inspect the gear splines for the following conditions:
    5. • Excessive wear
    • Spalling
    • Cracks
    • Twist
    • Corrosion
  5. Inspect the shaft splines for the following conditions:
    6. • Excessive wear
    • Spalling
    • Cracks
    • Distortion
    • Corrosion
  6. Inspect the retainer rings for the following conditions:
    7. • Excessive wear
    • Distortion
    • Damage
  7. Inspect the case halves for the following conditions:
    8. • Damaged or warped mating surfaces
    • Cracks
    • Porosity
    • Damaged thread holes
  8. Inspect the synchronizer stop rings for the following conditions:
    9. • Cracks
    • Chips
    • Spalling
    • Excessive wear
  9. Inspect the synchronizer hub and the sleeve for the following conditions:
    10. • Cracks
    • Chips
    • Spalling
    • Excessive wear
  10. Inspect the pads on the mode fork and on the range fork for the following conditions:
    11. • Wear
    • Distortion
  11. Inspect the oil pump gears and the case halves for the following conditions:
    12. • Spalling
    • Cracks
    • Damage
    • Wear
    • Replace the complete assembly if there is wear.
  12. Inspect the following components for excessive wear:
    13. • The input gear
    • The planetary carrier
    • The range shift hub tooth chamfers