Posted on: - 11/7/2025

2001–2010: Allison 1000 (5-Speed and 6-Speed)

  • Introduced with: LB7, LLY, LBZ, and LMM Duramax engines
  • Initial Version: 5-speed (2001–2005)
  • Updated to: 6-speed in 2006 (starting with the LBZ)
  • Key Features:
    • Tow/haul mode with grade braking
    • Lock-up torque converter
    • Integrated transmission control module (TCM)
    • Designed for medium-duty commercial use
  • Why It Stands Out: It was the first automatic transmission in a pickup truck capable of reliably handling over 500 lb-ft of torque out of the box. The Allison 1000 gave GM an edge over Dodge's 47RE/48RE and Ford's 4R100 and early 5R110W.

2011–2019: Allison 1000 6-Speed (LML and Early L5P)

  • Still Paired With: LML and early L5P Duramax engines
  • Torque Rating: Increased to handle up to 765 lb-ft
  • Emissions Integration: Added capability to manage downshifts and exhaust braking related to DPF and DEF systems
  • Notable Strengths: With regular maintenance, these transmissions regularly last beyond 200,000 miles. They also support moderate tuning without the need for internal upgrades.

2020–Present: Allison 10-Speed (10L1000)

  • Paired With: Updated L5P Duramax engines
  • Torque Rating: 910 lb-ft and above
  • Key Benefits:
    • Closer gear ratios for improved towing and fuel economy
    • Faster shifting and better drivability
    • Lower cruising RPMs at highway speeds
    • Reduced gear hunting under load
  • Design Collaboration: GM-branded “Allison 10-speed,” but co-developed with Allison Transmission and GM’s in-house teams. Still marketed as Allison due to the brand’s strong reputation.

Why the Allison Transmission Is So Respected

  1. Heavy-Duty Roots: Allison originally designed transmissions for tanks, buses, and commercial trucks. That DNA shows up in their overbuilt construction and torque handling.
  2. Smart Tuning: Shift logic is calibrated for real towing and work use, not just performance. Tow/haul mode, grade braking, and converter lock-up are all tuned to reduce heat and improve drivability.
  3. Aftermarket Support: The Allison 1000 and 10-speed have extensive support for performance upgrades, rebuild kits, valve bodies, and converters.
  4. Proven Longevity: With proper maintenance, Allison transmissions are known to last 250K miles. Many fleet and RV trucks still run original units.

Final Thoughts

From its launch in 2001 to today’s advanced 10-speed units, the Allison transmission has set the standard in diesel trucks. Whether you're towing, racing, or daily driving, Allison delivers proven performance and peace of mind.

Adam_Blog
By: Adam