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11-14 GM 6.6L Duramax Allison 6 Speed DHD Hardcore LML Transmission Cooler Line Set

The DHD Hardcore Hooker Line Kit replaces your damaged or leaking Duramax transmission cooler lines with the industries most comprehensive, trouble free, high quality line set available. DHD's Allison transmission cooler lines are the ONLY guaranteed leak-proof line set available in the aftermarket.


  • 100% New Factory GM Hard Lines
  • Stainless Steel Flex Wont Chafe, Dry Rot or Swell
  • In house TIG welded Construction
  • OE Routing and Fit
  • No Cutting, No Welding, No Compression Fittings
  • 10 -AN Threaded Connections Allow Easy Install and Serviceability of Surrounding Components.

This kit will work on all 2011-2014 Allison 6-Speed Transmissions and is a direct bolt-on that will utilize factory mounting clips and retainers. Installation is simple. Just remove your leaking factory hard lines, and replace with our DHD hardcore hooker line kit.

NOTE: Due to revisions in trans cooler mounting and hose routing these lines will not fit 2015 or 2016 Trucks.

DHD part number: 100-670

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