Owners of 2007-2011 Cadillac Escalade, Chevy Silverado and GMC Sierra, Yukon and Yukon XL, and 2008-2011 Chevy Avalanche, Suburban and Tahoe vehicles equipped with the 6L80 automatic transmission may complain about a tick or rattle noise at the front dash area. This may be caused by a cracked or broken transmission fluid filler tube (resulting in a resonance noise during certain driving conditions).
If the filler tube is not cracked or broken, the noise may also be caused by contact between the filler tube and the front of the dash area. Inspect for adequate clearance between the filler tube and the front of the dash area or any heater lines that might be in the area. Create a gap as needed.
If the transmission filler tube is to be replaced, it should be replaced with a revised filler tube that features a damper near the top that prevents resonance issues.