Vent Assembly
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, 2003 Chevrolet Cab & Chassis Silverado, and 2002 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
The vent assembly is located at the top left-rear of the transmission main housing. The vent assembly prevents air pressure buildup within the transmission. Its passage must be kept clean.
The amount of dust and dirt encountered will determine the frequency of vent assembly cleaning. Use care when cleaning the transmission. DO NOT spray steam or water or allow cleaning solution directly onto the vent assembly. This can force the water or cleaning solution into the transmission and contaminate the fluid.