This is the perfect transmission for your two-wheel drive towing and heavy-load trucking needs that range from 450 to 550 HP depending on the application. These units have valve body modifications that increase cooler flow and improve shift characteristics without the harsh feel of a racing style transmission. When used with a TCI Heavy-Duty Towing Torque Converter you can be sure the transmission package is tailored to provide long dependable service and maximum fuel economy. The optional low gear package offered with each of our RV units is a great addition for trucks pulling heavy loads.