GM 4L80E TRANSMISSION CASE 1999-03 (7 BOLT)
The 7-bolt GM 4L80E case fits a wide range of heavy-duty GM trucks, vans, and large SUVs from the early 1990s through the mid-2000s (roughly 1991-2007), including Chevy/GMC C/K, Silverado, Sierra, Suburban, Yukon, and Express/Savana models, as well as specialty vehicles like the Hummer H1 and some Bentley/Rolls-Royce applications, handling big-block/V8 engines. The “7-bolt” refers to the bellhousing pattern for specific engine families, common with 5.7L, 7.4L (Big Block), and later 6.0L/8.1L V8s.
Common Vehicle Fitment:
- Chevy/GMC Trucks & SUVs (2500/3500 Series): C/K, Silverado, Sierra, Suburban, Yukon (1991-2007), Avalanche 2500 (2002-2006).
- Vans: Chevrolet Express, GMC Savana (2500/3500 Series, 1991-2009).
- Specialty: Hummer H1 (1992-2006), some Rolls-Royce & Bentley models (early 90s).
Key Years & Engine Considerations:
- Early Models (1991-1994): Often paired with 7.4L (454) Big Blocks or 5.7L engines, featuring different cooler line setups and connectors.
- Mid-Period (1995-2000): Saw continued use with 5.7L, 7.4L, and the introduction of the 6.0L LS engines in the late 90s.
- Later Models (2000-2007+): Common with 6.0L and 8.1L (496ci) V8s, including the Avalanche 2500 and HD trucks.
Identifying Your Specific 4L80E:
- Check the ID Tag: Look for digits in the center of the transmission ID tag for the vehicle model year.
- Case Features: Later models (post-2004) often have a center bolt in the top of the bellhousing and a single cooler line fitting.
- Connectors: Early units used a bolt-on harness; later ones switched to a snap-on plug.
In summary, the 7-bolt 4L80E case is a robust unit for powerful GM RWD/4WD applications, primarily from the 90s and early 2000s, built to handle big torque.
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