Yes, the Allison transmissions are strong, but they are not bulletproof. High horsepower levels and heavy duty use stresses transmission parts past what they were originally designed to handle. The Allison's output shaft is a common failure point so PPE offers this Billet Output Shaft for high performance transmissions. The PPE shaft has been specially designed to withstand the higher horsepower and torque levels that naturally come with high performance engines or the added stress from towing or racing.