Sierra 3500 Denali 4WD V8-6.0L (2011)
10. Coat the perimeter of the access hole with RTV Silicone Sealant, GM P/N 12378521 (in Canada, 88901148) or equivalent, to seal the bare edge of
the metal.
11. Install the round body plug, GM P/N 15908858. Ensure that the plug is sealed with the silicone sealant.
12. Reinstall the floor covering and seat.
Cage Nut Access Using Rectangular Service Plug
Rectangular service holes have been provided in the floor of the cab to access the cage nut in all other cab mounting bolt locations. The service hole is
directly above the cab mount bolt. Use the following steps to remove and replace the service plugs that cover the service hole.
1. Remove the seat located above the affected bolt. Refer to SI for the applicable seat removal steps.
2. Remove the sill trim plate. Refer to Front Side Door Sill Trim Plate Replacement in SI.
3. Partially remove (pull back) the floor covering (carpet) to expose the rectangular service plug.
4. Using a gasket scraper or similar tool, pry off and discard the rectangular floor plug.
5. Service the cab mounting bolt and nut as required.
