INTRODUCTION The dry dual clutch transmission, dDCT, uses dual concentric input shafts and two counter shafts which are in constant mesh with the final drive ring gear on the output axis with the differential assembly. Engine power is transferred to the transmission using a dual mass flywheel, DMF, with interface drive tangs to the dual dry clutches, DDC. Power flow from the DDC to the concentric input shafts is handled by a high pressure, direct acting dual concentric slave cylinder, CSC. All transfer pinions and gears are in constant mesh, with gears on the countershafts achieving power transfer through appropriate synchronizer assembly engagement between the gear and splined synchronizer hub. Four synchronizer assemblies are incorporated to achieve the reverse and seven forward gear ranges. Synchronizers are applied using hydraulic power from the control system. Power flow from the countershaft final drive pinion is routed to the final drive ring gear mounted to the differential assembly. Final drive ratio flexibility is achieved by matching final drive ring gear with the integrated final drive pinions on the countershafts. Lubrication of the gear box components is achieved by directed splash lubrication methods, incorporating troughs and dams, using fluid engineered for minimal spin loss throughout the operating temperature range. Creative engineering solutions, such as routing the power flow for reverse gear through both countershafts, enabled reduced packaging length and elimination of a separate axis for a reverse idler gear.A separate hydraulic fluid is used in the control system, referred to as the powerpack, for the electronically controlled shift events. The fluid is engineered to maximize pump efficiency across the operating temperature range, specifically cold temperature. A high pressure, axially compensated pump, driven by an electric motor, coupled with a gas charged accumulator, supplies the hydraulic power for the synchronizers and CSC. The accumulator enables the electric motor to be cycled as demand pressures require, as well as engine start / stop for fuel efficiency. The control system utilizes a direct mounted external controller to coordinate all shift events. Five pressure control solenoids, and four flow control solenoids are utilized in the hydraulic circuitry. Design for manufacturability methods were incorporated into the components and architecture of the transmission throughout the engineering and design process. Manufacturing flexibility for customer specific component interface requirements, sediment control, and error proofing methods significantly contribute to achieving the transmission durability, cost, and reliability goals. System integration of the transmission into the vehicle environment has resulted in noise, vibration, and handling characteristics competitive with conventional automatic transmission based vehicles. A summary of the dDCT transmission specifications are shown in Table 1 .General Motors Front Wheel Drive Seven Speed Dry Dual Clutch Automatic Transmission Kirby S. Clark, Tejinder Singh, Ronald P. Buffa, Jack M. Gayney, William L. Cousins, Zhe Xie, Steven P. Moorman, Alexandria Wilson, Michael P. Fannin, Mark L. Graham, Christopher B. Preston, Michael B. Solt, David J. Varda, Mark R. Gilmore, Martin G. Foulkes, and Rebecca K. Risko General Motors Co. ABSTRACT General Motors has introduced a new front wheel drive seven speed dry dual clutch automatic transmission in 2014. The 250 Nm input torque rated gear box was designed and engineered for a global market in both front wheel drive and all-wheel drive configurations. The transmission has integrated start/stop capability enabled by the use of an electric motor driven pump and a pressurized accumulator. The architecture selected was chosen for optimization of packaging, fuel economy , mass, shift pleasability , and NVH. High mileage durability and world class drivability