At Next Gen Diesel, we offer excellent support for GM's Allison 10L1000 Transmission, as used in the 6.6L DuraMax Silverado/Sierra! GM began using the Allison 10L1000 Transmission in these trucks in model year 2020, as successor to the 6 Speed Allison, and currently uses this transmission today. Our product catalog includes complete transmissions, total rebuild kits, valve bodies, torque converters and parts. View our Allison 10L1000 transmissions and parts here!