Oil Pump Cleaning and Inspection
WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
- Clean all components in cleaning solvent and air dry.
- Inspect the transfer case oil pump assembly (1). Replace the oil pump assembly if end play is evident or if there is any sign of binding. End play can be measured by inserting a feeler gauge (3) between the outer rotor and housing. If the end play is equal to or greater than 0.1 mm (0.004 in), replace the oil pump assembly. Do not disassemble the oil pump it is serviced as an assembly.
- Inspect the transfer case oil pump suction pipe (2). Replace the oil pump suction pipe if the screen is embedded with debris.