6L80 and 6L90 share the same case and most internals. The 6L90 is the HD version. Here is what is actually different and what parts swap.
Shop the parts for this fix
Doing the whole job? 6L80 Advanced Rebuild Kit - Frictions & Steels, Gaskets & Seals, Filter, Shift Kit, Servo (5-Piece) — $228.99 $240.99 (save 5% vs buying separately)
Or grab the individual parts:
External identification
6L80 (2006-2014):
- 17-bolt pan
- 6-speed automatic
- ~440 ft-lb input rating
- Used in Camaro SS, Silverado 1500, Tahoe
6L90 (2007-2017):
- Same 17-bolt pan
- 6-speed automatic
- ~590 ft-lb input rating
- Used in Silverado 2500/3500, Express HD, Suburban
What is HD about the 6L90
Wider clutches:
- 6L80: 5-disc 1-2-3-4 clutch
- 6L90: 6-disc 1-2-3-4 clutch
- ~30% more clamp force
HD planetary:
- 6L80: stamped carriers
- 6L90: forged carriers
- Higher torque rating
HD output shaft:
- 6L80: 28-spline
- 6L90: 32-spline
- Different driveshaft / yoke
What parts interchange
Same between both:
- Pan and gasket
- Filter
- Valve body (most years)
- Solenoid pack
- Pump assembly
- Most seals and bushings
Different:
- Clutches (count discs)
- Planetary set
- Output shaft and yoke
- Some bell housing bolt patterns
Upgrading 6L80 with 6L90 parts
Worth doing during rebuild:
- 6L90 clutch packs (more frictions)
- HD planetary
- HD line pressure tune
- Adds ~100-150 ft-lb capacity
- $400-$700 extra over basic rebuild
Not bolt-in:
- Output shaft (different yoke)
- Some bell housings (Vortec vs LS rear)
When to choose 6L90 over 6L80
6L90 required if:
- Towing 8,000+ lbs regularly
- 3/4-ton or 1-ton truck
- Heavy fleet/work use
- Tuned 6.0L or 6.2L with sustained load
6L80 fine if:
- Daily driver / commuter
- 1/2-ton truck
- Stock tune
- Light occasional towing
Cost
6L80 rebuild:
- Parts: $400-$800
- Labor: $1,800-$2,800
- Total: $2,200-$3,600
6L90 rebuild:
- Parts: $500-$900
- Labor: $1,800-$2,800
- Total: $2,300-$3,700
6L80 with HD 6L90 parts:
- Parts: $700-$1,200
- Labor: $1,800-$2,800
- Total: $2,500-$4,000
Need 6L80, 6L90, or HD upgrade parts? Shop our 6L80/6L90 catalog. HD clutches, planetary sets, complete rebuild kits. Free shipping over $70.
Related: