The factory stamped steel flex plate found on the 2001-2005 GM 2500HD / 3500 automatic transmissions is inadequate for the capabilities of the engine to say the least. All too often, we see shattered flex plates that will ruin your day at the track, camping, or wherever. ATS offers their billet flex plate that will match up perfectly to any stock or aftermarket torque converter behind your Duramax. Especially if you have upgraded your torque converter to an aftermarket triple or higher disc count, we would consider this a required add-on to prevent future failures.