| Where to BuyThe 10L1000 transmission is a ten speed automatic transmission designed by GM engineers and validated through rigorous Allison engineer testing. The 10L1000 was developed for the 2500/3500 heavy duty series 2020 GMC Sierra and Chevy Silverado with the 6.6L Duramax diesel engine. The 10L1000 transmission is manufactured with high strength parts and reduces high heat buildup at high loads with its first gear torque converter lock-up ability.
