Full-time four-wheel drive transmission with limited slip clutch

A transmission for use in a four-wheel drive motor vehicle having an engine and front and rear drivelines, said transmission comprising:

• an input shaft adapted to be driven by the engine;
• a mainshaft;
• a front output shaft adapted to drive the front driveline;
• a rear output shaft adapted to drive the rear driveline;
• constant mesh gearsets which can be selectively engaged to couple said mainshaft to said input shaft for driven rotation at predetermined speed ratios, said constant mesh gearsets including a first input gear rotatably supported on said input shaft, a first compound gear rotatably supported on said mainshaft and having a first drive gear meshed with said first input gear and a second drive gear, a second compound gear rotatable supported on said input shaft and having a second input gear meshed with said second drive gear and a third input gear, a third drive gear rotatable supported on said mainshaft and meshed with said third input gear, a first synchronizer clutch for selectively coupling one of said first and second input gears to said input shaft, and a second synchronizer clutch for selectively coupling one of said second and third drive gears to said mainshaft;
• a planetary gearset having a sun gear driven by said mainshaft, a ring gear, a carrier, and a pinion gear meshed with said sun gear and ring gear and which is rotatably supported on said carrier;
• an interaxle differential for transferring drive torque from said carrier to said front and rear output shafts while permitting speed differentiation therebetween, said interaxle differential having an input member driven by said carrier, a first output member driving said front output shaft, and a second output member driving said rear output shaft;
• a range clutch which can be selectively engaged to couple said ring gear to said mainshaft for driving said input member at a first speed ratio relative to said mainshaft, said range clutch can further be selectively engaged to couple said ring gear to a stationary member for driving said input member at a second speed ratio relative to said mainshaft;
• a transfer clutch for controlling the torque distribution and speed differentiation between said front and rear output shafts by varying a clutch engagement force exerted on a clutch pack, said transfer clutch including a thrust mechanism operable in a first position to establish a minimum clutch engagement force and in a second position to establish a maximum clutch engagement force, and an actuator for moving said thrust mechanism;
• sensor means for detecting an operating characteristic of the vehicle and generating a sensor input signal in response thereto;
• and
• a controller for receiving said sensor input signal and controlling actuation of said actuator in accordance with the magnitude of said operating characteristic.