The 4L80E and 6L80 are both GM HD transmissions but they're very different. Picking the right one for your build matters. Here's the comparison.
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Quick overview
4L80E (1991-present):
- 4-speed automatic
- Heavy-duty rating
- ~440 ft-lb stock capacity
- Mechanical / TCM controlled
- Read our best 4L80E rebuild kit
6L80 (2006-present):
- 6-speed automatic
- ~470 ft-lb stock capacity
- Integrated mechatronics
- Read our best 6L80 rebuild kit
Gear ratios
4L80E:
- 1st: 2.48
- 2nd: 1.48
- 3rd: 1.00
- 4th: 0.75 (overdrive)
6L80:
- 1st: 4.03
- 2nd: 2.36
- 3rd: 1.53
- 4th: 1.15
- 5th: 0.85
- 6th: 0.67
Result:
- 6L80 has much lower 1st (better off-the-line)
- 6L80 has wider gear spread
- 6L80 better MPG at cruise
- 4L80E simpler (fewer gears = fewer failures)
Strength comparison
Stock capacity:
- 4L80E: ~440 ft-lb
- 6L80: ~470 ft-lb
With HD upgrades:
- 4L80E: 700+ ft-lb (well-known parts)
- 6L80: 600-700 ft-lb (newer aftermarket support)
HD aftermarket maturity:
- 4L80E: extensive (Sonnax billet everywhere)
- 6L80: developing (improving rapidly)
Read our Sonnax HD comparison
Application notes
4L80E applications:
- 2500/3500 HD trucks
- Express vans
- Older Suburban
- Aftermarket performance swaps
6L80 applications:
- 2007-2014 1500-series (Silverado/Sierra)
- 5.3L/6.2L gas applications
- Some Camaro Z28/SS
- Newer Tahoe/Yukon
Read our 4L60E vs 6L80 comparison for related
Electronics
4L80E:
- Older electronic design
- Solenoid pack with limited capability
- Standalone controller easy (B&M, TCI)
- Read our 4L80E PWM solenoid
6L80:
- Modern mechatronics (sealed unit)
- More precise control
- TCM integrated
- Read our 6L80 mechatronics rebuild
Implications:
- 4L80E easier for swaps (independent control)
- 6L80 better OEM integration
- 4L80E cheaper to control standalone
Rebuild cost
4L80E:
- DIY: $800-1,500
- Shop: $2,000-3,500
- HD: $2,500-4,500
- Read our best 4L80E rebuild kit
6L80:
- DIY: $1,000-1,800
- Shop: $2,500-4,500
- HD: $3,500-5,500 (mechatronics expensive)
- Read our 6L80 rebuild cost guide
Difference: 6L80 ~10-20% more
When to choose 4L80E
Best for:
- Engine swap into pre-2007 truck
- HD tow rig
- Cost-sensitive HD build
- Race/performance with aftermarket HP gains
- Read our TH400 to 4L80E swap
Why:
- Simpler electronics (easier swap)
- Lower rebuild cost
- More aftermarket support
- Read our 4L60E to 4L80E swap
When to choose 6L80
Best for:
- 2007+ truck with 5.3L/6.2L
- Daily driver
- MPG concerns
- Modern feature integration
Why:
- Better gear spread = better MPG
- Lower 1st gear = better acceleration
- Modern integration
- Lower RPM at highway
Common failures
4L80E:
- Center support sealing rings
- Intermediate sprag
- Solenoid pack
- Read our 4L80E common failure codes
6L80:
- TCC PWM shudder (famous)
- Wave plate
- Input drum
- Read our 6L80 common failure codes
Maintenance differences
4L80E:
- Standard ATF Dexron VI
- Drain pan + filter
- Read our how to flush transmission fluid
6L80:
- Standard ATF Dexron VI HP for newer
- More complex service (mechatronics consideration)
- Premium fluid recommended
Read our transmission fluid types
Aftermarket HD parts
4L80E:
- Sonnax billet everywhere
- Multiple HD options
- Mature market
6L80:
- Sonnax billet developing
- HD wave plate, input drum
- Improving year-over-year
- Read our 6L80 wave plate replacement
Direct comparison summary
Daily driver:
- 6L80 better (gears, MPG)
HD tow rig:
- 4L80E better (parts, simplicity)
Performance build:
- 4L80E better (HD support, simpler controls)
Stock truck retention:
- Keep whatever you have
Engine swap (older truck):
- 4L80E if pre-2007
- 6L80 if 2007+ donor
Race / serious power:
- 4L80E (with full HD bundle)
Need 4L80E or 6L80 parts? Shop our complete catalog. Both rebuild kits, HD Sonnax upgrades, complete parts catalog. Free shipping over $70.
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