The Allison 1000 torque converter is the bottleneck on tuned Duramax trucks. Stock dies at 500 ft-lb. HD triple-disc handles 1,000+. Here is the full guide.
Why the stock converter fails
Single-disc TCC clutch:
- Stock converter: 1 friction disc
- Limited apply force
- Slips on tuned Duramax
- Slip = heat = clutch fails
Torque capacity:
- Stock rating: ~500 ft-lb sustained
- Stock Duramax: 520 ft-lb (LB7) to 765 ft-lb (LMM)
- Even stock LMM/LMG exceeds stock converter
Symptoms of converter failure
- TCC shudder (especially under load)
- P0741 (TCC stuck off)
- Burnt fluid smell
- Slip on grade with TCC commanded on
- Brown / black flake in fluid
- Sometimes: complete TCC failure
Replacement options
OEM single-disc:
- $300-$600 part
- Same failure mode
- Stock truck only
HD single-disc (upgraded friction):
- $500-$800
- Improved friction material
- Good for light tow / stock Duramax
SunCoast triple-disc:
- $1,200-$1,800
- 3 friction discs (3x clamp force)
- Rated 1,000+ ft-lb
- Standard upgrade for tuned LB7-LMM
ATS Five Star multi-disc:
- $1,800-$2,500
- Highest capacity Allison converter
- Rated 1,200+ ft-lb
- Required for 800+ HP builds
Goerend triple-disc:
- $1,400-$2,000
- Premium build quality
- Strong warranty
What you need to know about stall RPM
Stock converter:
- ~1,800 RPM stall
- Smooth daily driver feel
Tow-tuned converter:
- 1,800-2,200 RPM stall
- Holds gears longer for towing
High-stall converter:
- 2,400-2,800 RPM stall
- Aggressive launches
- Race trucks only
Install
- Trans must come out
- Pulled from trans (front)
- Push new converter onto input shaft (engage splines)
- 3-stage engagement: pump, splines, stator support
- Verify converter spins freely after install
- Trans installed with converter pre-loaded onto trans
Cost
DIY converter swap (with rebuild):
- HD triple-disc: $1,200-$1,800
- Front pump seal: $30-$60
- Pump bushing (always): $30-$60
- Fluid (TES-295, 18 qts): $250-$400
- Total: $1,510-$2,320
Shop install:
- Parts: $1,510-$2,320
- Labor: $1,500-$2,500 (trans R&R)
- Total: $3,010-$4,820
Pair with HD clutches (C2)
- HD converter passes more torque to clutches
- Stock C2 fails after converter upgrade
- Read our Allison 1000 C2 clutch pack
Pair with HD tune
- EFILive or HP Tuners
- Raised line pressure
- Custom TCC apply ramp
- Required to fully use HD converter
When to upgrade
Triple-disc required if:
- Stock or tuned LB7-LMM truck
- Towing 12k+ lbs
- Building over 500 HP
- Already shuddered stock converter
OEM fine if:
- Stock LBZ/LMM
- Light load use
- Service replacement only
Need Allison 1000 torque converter, HD upgrade, or full rebuild? Shop our Allison catalog. OEM and HD triple-disc converters, complete rebuild kits. Free shipping over $70.
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