Allison used three torque converter generations on the 1000 series. Each has different strength and lockup behavior. Here's what's different.
TC1 (2001-2005)
- Single disc TCC
- Weakest of the three
- Found in 6.6L LB7 Duramax era
- Susceptible to TCC failure with HP
- Read our Allison 1000 TCC apply
TC2 (2006-2010)
- Updated lockup clutch design
- Improved TCC durability
- LMM/LBZ Duramax era
- Better than TC1 but still struggles with tunes
TC3 (2011+)
- Triple disc TCC
- Significantly stronger
- LML Duramax era
- Best stock unit for HD use
- Reduces shudder risk
Upgrade path for older trucks
- TC3 will physically swap into earlier Allison 1000
- Better strength and TCC reliability
- Requires TCM tune adjustment
- Cost: $700-$1,500 reman TC3
HD aftermarket converters
- BD Diesel, Suncoast, ATS
- Triple-disc HD designs
- 1000+ ft-lb capacity
- $1,200-$2,500
Symptoms TCC needs replacement
- Shudder at cruise
- Slipping
- Pan debris
- Read our torque converter failure symptoms
When to upgrade
- Tuned 6.6L Duramax
- Heavy tow with mod engine
- Older 1000 series with TC1 stuck shudder
- Read our diesel tow rig setup
Identify which TC you have
- Year of truck (matches Duramax generation)
- Allison tag decode
- Or visual at TC bolt pattern
- Read our GM trans serial decoder
Replace during rebuild
- Always replace TC during major rebuild
- Upgrade to TC3 or HD aftermarket
- Pair with HD apply components
- Read our best Allison 1000 rebuild kit
Need Allison TC or rebuild parts? Shop our Allison catalog. Converters, HD upgrades, rebuild kits. Free shipping over $70.
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