Methods of controlling a tandem axle assembly in a vehicle, the tandem axle assembly including an inter-axle differential (IAD), one or more side gears, and a front tandem axle assembly having a pair of front tandem axle half shafts selectively connected to a pair of front tandem axle wheel hub assemblies. When a determined speed of the vehicle is greater or equal to a predetermined speed, the IAD may be locked, the tandem axle wheel hub assemblies may be disconnected from their respective tandem axle shafts, and/or the IAD may be moved out of engagement with the one or more side gears. When a determined speed of the vehicle is less than a predetermined speed, the IAD may be unlocked, the tandem axle wheel hub assemblies may be connected to their respective tandem axle shafts, and/or the IAD may be engaged with the one or more side gears.

A differential drive system for a vehicle includes a differential drive device, a dog clutch device, and an electromagnetic actuator. The axis of rotation of the differential drive device is situated outside of the annular electromagnet of the electromagnetic actuator.

A method and system for controlling a wheel slip of a vehicle without using a reference speed is provided. The system includes a speed detector that detects a speed of a driving device for operating the vehicle and a controller that determines a torque calibration command based on a torque command of the driving device, and a current speed and a past speed of the driving device detected by the speed detector. The torque command of the driving device is calibrated using the determined torque calibration command, and a driving device is operated based on the calibrated torque command.

A method and system for controlling a wheel slip of a vehicle without using a reference speed is provided. The system includes a speed detector that detects a speed of a driving device for operating the vehicle and a controller that determines a torque calibration command based on a torque command of the driving device, and a current speed and a past speed of the driving device detected by the speed detector. The torque command of the driving device is calibrated using the determined torque calibration command, and a driving device is operated based on the calibrated torque command.

A vehicle includes front suspension assemblies; rear suspension assemblies; a left driven wheel and a right driven wheel with first left and right brake assemblies; a left wheel and a right wheel with second left and right brake assemblies; an anti-lock braking system (ABS) module; a drive mode coupler connected between the transmission and the left and right wheels for changing between a 24 and a 44 drive configuration; and a drive mode switch for controlling the drive mode coupler, the ABS module selectively performing brake traction control of at least one wheel based on the position of the drive mode switch. A method for controlling traction of the vehicle includes sensing the drive mode switch position and when the drive mode changes from a 24 position to a 44 position, causing the ABS module to perform brake traction control on at least one wheel.

In accordance with one aspect of the techniques described herein, there is provided a vehicle comprising an engine, an automatic, robotic, or continuously variable transmission mechanically coupled to the engine, a four-wheel drive system, a vehicle control system coupled to the engine, the four-wheel drive system and the transmission, a braking system, a gas pedal for controlling the operation of the engine, a brake pedal for controlling the operation of the braking system, the gas pedal and the brake pedal being disposed in the vehicle for control by a right foot of the driver, the vehicle further comprising an additional pedal being disposed in the vehicle for control by a left foot of the driver and coupled to the vehicle control system, wherein the additional pedal is separate and distinct from the brake pedal and the gas pedal and wherein additional pedal controls the four-wheel drive system of the vehicle.

A vehicle including a coupling device that includes (a) an engagement clutch mechanism for coupling an input side engagement member that is coupled to a drive power source of the vehicle and an output side engagement member that is coupled to a drive wheel of the vehicle; and (b) a cam mechanism for assisting engagement of the input and output side engagement members depending on a differential torque by which the input and output side engagement members are rotated differentially. The vehicle includes a control device configured, when the engagement of the input and output side engagement members is to be released, to cause a braking force to be applied to one of the input and output side engagement members such that the differential torque is reduced.

A vehicle including a coupling device that includes (a) an engagement clutch mechanism for coupling an input side engagement member that is coupled to a drive power source of the vehicle and an output side engagement member that is coupled to a drive wheel of the vehicle; and (b) a cam mechanism for assisting engagement of the input and output side engagement members depending on a differential torque by which the input and output side engagement members are rotated differentially. The vehicle includes a control device configured, when the engagement of the input and output side engagement members is to be released, to cause a braking force to be applied to one of the input and output side engagement members such that the differential torque is reduced.

A disconnect assembly, including: a selector; a first clutch including a first sleeve; and a second clutch including a second sleeve. In a drive mode, the first sleeve non-rotatably connects a first drive gear and a first axle of a first drive train, and the second sleeve is non-rotatably connects a second drive gear to a second axle of a second drive train. In a disconnect mode, relative rotation between the first drive gear and the first axle is enabled and relative rotation between the second drive gear and the second axle is enabled. To transition from the drive mode to the disconnect mode, the selector is displaced by an actuator, the selector is arranged to disconnect the first annular sleeve from the first drive gear or the first axle, and the selector is arranged to disconnect the second annular sleeve from the second drive gear or the second axle.

A disconnect assembly, including: a selector; a first clutch including a first sleeve; and a second clutch including a second sleeve. In a drive mode, the first sleeve non-rotatably connects a first drive gear and a first axle of a first drive train, and the second sleeve is non-rotatably connects a second drive gear to a second axle of a second drive train. In a disconnect mode, relative rotation between the first drive gear and the first axle is enabled and relative rotation between the second drive gear and the second axle is enabled. To transition from the drive mode to the disconnect mode, the selector is displaced by an actuator, the selector is arranged to disconnect the first annular sleeve from the first drive gear or the first axle, and the selector is arranged to disconnect the second annular sleeve from the second drive gear or the second axle.