GM is exhausting
Some customers may complain about an exhaust leak and/or noise, described as a rattle or rumble. The condition may be caused by an unseated pipe-to-pipe mid-joint connection.
This applies to 2009-2011 Cadillac Escalade Hybrid; 2011 Cadillac Escalade, Escalade ESV and Escalade EXT; 2009-2011 Chevrolet Avalanche, Silverado 1500, Suburban, Tahoe and Tahoe Hybrid; 2009-2011 GMC Sierra 1500, Yukon, Yukon Hybrid and Yukon XL, equipped with the 4.3L, 4.8L, 5.3L or 6.0L engine; 2011 Chevrolet Avalanche, Silverado and Suburban; and 2011 GMC Sierra, Sierra Denali, Yukon Denali, Yukon XL, Yukon Denali XL, all equipped with the 6.2L engine.
Remove and discard the exhaust band (Norma clamp). Install and carefully position a new Norma clamp to the pipe joint. Firmly push and hold the pipes together while tightening the Norma clamps bolt. Tighten the bolt to a value of 21 lb-ft (28 Nm). Note: After the clamp is installed, it does not need to be perpendicular to the pipe. It is acceptable to have a pipe-to-pipe or clamp angle.
Confirm that the clamp edges (both sides of the clamp, all the way around the clamp) are fully seated on the pipe. Run the engine and inspect the clamp joint to ensure that there are no leaks.