Abstract: A method and system of controlling a drive-neutral-drive (D-N-D) shift in a multi-speed transmission. The method includes receiving a drive to neutral (D-N) shift request followed by a neutral to drive (N-D) shift request; initiating a drive to neutral (D-N) shift and determining an attained gear; determining a scheduled gear; determining if the scheduled gear is equal to the attained gear; and determining whether an off-going clutch for the drive to neutral (D-N) shift is in a hold state. The method further includes (I) aborting the drive to neutral (D-N) shift when (i) the scheduled gear is not equal to the attained gear and (ii) the off-going clutch for the (D-N) shift is in the hold state, or (II) completing a shift to neutral (N) when the off-going clutch for (D-N) shift is not in the hold state followed by shifting back drive (D).

Abstract: A dual mass flywheel protection system includes an engine coupled to a transmission using a dual mass flywheel defining a drive train. A gear determiner identifies a present operational gear. A filtered engine speed is available. A torque reduction module applies the present operational gear and filtered engine speed producing signals limiting an engine torque to reduce engine torque variations. A first torque limitation option limits engine torque when the drivetrain is coupled, dependent on an engine rpm, which is related to an actual gear selected. A second torque limitation option determines an engine torque reduction during an emergency braking maneuver while an anti-lock brake (ABS) system is active. An engine shut-off module produces an output signal shutting off the engine upon initiation of one of multiple engine shut-off module outputs, and is active when an engine torque limitation due to a low engine rpm is not present.

Abstract: A hybrid transmission device includes six planetary gear sets mechanically-operatively connected to an internal combustion engine and two motor/generators adapted to selectively transmit mechanical power to an output member through selective application of eight caliper brake systems. Each planetary gear set has a sun gear and a ring gear, each of which meshingly engage a plurality of planet gears. The first and second motor/generators are coaxially aligned with each other as well as six planetary gear sets. The sun gear in the first planetary gear set is connected to the first motor/generator. The sun gear in the second planetary gear set is connected to the second motor/generator. Various driving modes are provided by changing the states of the caliper brake systems and the operating modes of the engine and the first and second motor/generators.

Abstract: An automatic transmission of this invention includes a plurality of engaging mechanisms, and the plurality of engaging mechanisms include a mechanical engaging mechanism that functions as a brake. The mechanical engaging mechanism can switch a rotational element between a first state in which rotation is restricted only in one direction and a second state in which rotation is restricted in both directions. When switching from the first state to the second state, engagement control is started in advance for at least one of the plurality of engaging mechanisms to be set in an engaging state.

Abstract: A planetary gearbox with substantial speed reduction includes a stationary spindle, an integral service brake, and a parking brake. The integral service brake resides radially outwardly with respect to the parking brake in a stacked arrangement such that axial space is conserved yielding an axially short and compact gearbox. An oil passageway extends radially through the spindle. A rotating input shaft drives the planetary gearbox and produces an output in the form of a rotatable housing/hub. The service brake rotors have a large surface area and are keyed to the rotatable hub enabling efficient brake cooling and efficacious brake performance in a compact arrangement.

Abstract: A control apparatus for an automatic transmission including three frictional engagement elements is configured to set engagement pressures of first and second frictional engagement elements at the time when a predetermined shift speed is established such that a torque capacity of a third frictional engagement element becomes smaller than torque capacities of the first and second frictional engagement elements in the case where an engagement pressure is generated in the third frictional engagement element at the time when the predetermined shift speed is established.

Abstract: A method of controlling a pump for a hybrid transmission includes commanding a first line pressure of the transmission and deriving a first torque value—an open-loop torque value—from the first line pressure command, and commanding the pump to operate at the first torque value. The method monitors actual speed of the pump and derives a second torque value—a closed-loop torque value—therefrom. A third torque value is derived from the first and second torque values, and the pump commanded to operate at the third torque value. A first speed value may be derived from the first line pressure command, and the second torque value derived from the difference between the monitored and the first speed values. Deriving the third torque value may include a substantially-linear combination of the first and second torque values.

Abstract: Construction of a continuously variable transmission device for a vehicle is achieved that, when a shift lever is shifted to a selection position for a direction opposite the traveling direction at that time, it is capable of preventing the vehicle from continuing to travel at high speed in a direction opposite the direction intended by the operator. When the shift lever is shifted to a selection position of a direction opposite the traveling direction at that time, and the vehicle speed is faster than a specified speed (V1), the connection of a clutch device that transmits power between a continuously variable transmission mechanism and a differential gear mechanism is disconnected, and the drive force from the drive source is prevented from being further transmitted to the wheels.

Abstract: A method for controlling a transmission gear change to a desired gear includes disengaging an offgoing transmission control element, changing engine speed to a synchronous speed of the desired gear, decreasing engine output torque, and engaging an oncoming transmission control element.

Abstract: A control apparatus of an automatic transmission including a start intended operation detecting unit detecting a vehicle starting operation; and a clutch control unit engaging the clutch from the clutch disengaged state and the automatic speed change mechanism is placed in a neutral state, when the vehicle starting operation is detected. The clutch control unit includes an initial engagement control unit performing initial engagement control that starts frictional contact of the clutch by supplying hydraulic pressure to a hydraulic servo of the clutch, and a slip start control unit establishing a speed ratio of the automatic speed change mechanism at the start by slip-controlling the clutch after the initial engagement control is terminated, thereby increasing output shaft rotational speed of the automatic speed change mechanism without reducing the input shaft rotational speed of the automatic speed change mechanism to less than the input shaft rotational speed at the end of initial engagement control.

Abstract: A method of operating a vehicle drive train having a drive machine, a transmission apparatus having a plurality of shift elements and an output drive. The plurality of shift elements are engaged or disengaged in a power flow for achieving different transmission ratios within the transmission apparatus. The output drive is coupled to a transmission output shaft and the drive machine is coupled to a transmission input shaft of the transmission apparatus. Upon a request to interrupt power flow within the transmission apparatus, between the transmission input shaft and the transmission output shaft, a maximum number of shift elements are transferred to and/or held in an engaged operating state, and the remaining portion of the shift elements are transferred to and/or held in a disengaged operating state with the transmission output shaft being rotatable.

Abstract: A control device for a vehicle continuously variable transmission 4 includes: final speed ratio setting means for setting an overall speed ratio of the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 to be reached on the basis of an operating condition of the vehicle as a final speed ratio; shift control means for controlling the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 such that the overall speed ratio aligns with the final speed ratio at a predetermined transient response; stagnation determining means for determining whether or not a stagnation period in which the overall speed ratio stops varying will occur during an upshift; and reduction control means for shortening a time required to advance to an inertia phase from a start of a shift in the subtransmission mechanism 30 following a determination that the stagnation period will occur.

Abstract: A vehicle includes a pump configured to output fluid at a commanded pressure when driven by a motor. A first hydraulic device is operably connected to the pump and configured to operate in response to receiving fluid at a first pressure. A second hydraulic device is operably connected to the pump and configured to execute a shift command in response to receiving fluid at a second pressure. A control processor is configured to control the commanded pressure in accordance with a priority scheme. That is, the control processor is configured to direct at least a portion of the commanded pressure from the first hydraulic device to the second hydraulic device for a duration of a shift command based on the priority scheme and redirect at least a portion of the commanded pressure to the first hydraulic device upon completion of the shift action.

Abstract: A manual valve disconnects a line pressure oil passage and an R position pressure oil passage when a selector is in a D position or an N position and causes the R position pressure oil passage and the line pressure oil passage to communicate when the selector is in an R position. A switching valve is switched to disconnect a low & reverse brake pressure oil passage and the R position pressure oil passage when the selector is in the D position or the N position and a vehicle is driving at a vehicle speed equal to or lower than a predetermined vehicle speed.

Abstract: A method for controlling torque converter slip includes operating the torque converter in a controlled slip mode, monitoring slip in the torque converter, statistically analyzing the monitored slip to determine a likely condition of the torque converter, and utilizing the likely condition of the torque converter to control the torque converter slip.

Abstract: An control apparatus for an automatic transmission includes: a failure shift stage setting section configured to set, to the target shift stage, a shift stage which can be attained in a state in which the one of the solenoids judged that the failure is generated is not energized; and a failure neutral state through section configured to control the solenoids at a predetermined vehicle speed or over so that the automatic transmission is brought to a neutral state, when the target shift stage is a shift stage at which the vehicle speed is suddenly decreased when the solenoids are controlled so that the automatic transmission attains the target shift stage, and to control the solenoids below the predetermined vehicle speed so that the automatic transmission attains the target shift stage.

Abstract: A method for operating a motor vehicle hybrid powertrain having an engine, a motor-generator and a multi-speed automatically-shiftable transmission, wherein the engine and the motor-generator operate to supply torque to the transmission for driving a vehicle. The method includes modulating the torque supply from the motor-generator to the transmission during a gear shift to minimize a transmission output torque disturbance.

Abstract: A hydraulic control system for a automatic transmission includes a plurality of solenoids and valves in fluid communication with a plurality of shift actuators. The shift actuators are operable to actuate a plurality of torque transmitting devices. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the shift actuators. The solenoids are configured to provide a forward gear ratio and a reverse gear ratio when the solenoids are deengerized.

Abstract: Rotation-stop determining portion queries as to whether the first rotary element is lowered in a rotation speed to be stopped during an engine drive mode. If the answer is YES and differential-portion rotation speed determining portion makes a positive determination, then engaging-element control-executing portion executes engaging element control. This allows a third rotary element of the differential portion, connected to drive wheels via an engaging element of an automatic shifting portion, to approach a state available to freewheel. This prevents a second rotary element and a first electric motor from reaching high-speed rotations caused by a decrease in rotation speed of the first rotary element in a stop direction and a differential action of the differential portion. This enables the prevention of a durability decrease of a power distributing mechanism and the first electric motor.

Abstract: An electrically variable transmission (EVT) selectively establishes various EVT modes and a neutral mode. The EVT includes a source of pressurized fluid, fluid-actuated clutches, various solenoid-actuated valves including trim valves and blocking valves adapted to control a flow of pressurized fluid to the clutches to establish the transmission operating modes, and an electronic control unit (ECU). The ECU actuates different combinations of the solenoid-actuated valves to establish the different transmission modes. The solenoid-actuated valves are configured in such a manner as to provide the EVT with one or more default operating modes in the event the ECU temporarily loses electrical power. Depending on the particular configuration, the default modes can be the neutral mode alone, or the neutral mode combined with one or more of the EVT modes, with the EVT modes enabled by providing one or both of the blocking valves with a latching feature.

Abstract: An automatic transmission of a motor vehicle, comprising a plurality of planetary gear units; a plurality of frictional elements, the frictional elements assuming engaged/disengaged condition upon receiving a ratio change instruction thereby to establish a desired speed of the transmission with the aid of the planetary gear units; a deceleration detecting means that detects a deceleration of the motor vehicle; a gear ratio detecting means that detects an actual gear ratio that is actually established in the transmission; and an interlock judgment means that judges whether or not the transmission is subjected to an interlock, the interlock being a condition wherein upon receiving the ratio change instruction, at least one of the frictional elements is brought into unintended engagement.

Abstract: An automatic transmission includes a planetary gear mechanism, an engagement element group including a particular engagement element having first and second pressure chambers, a pressure control valve to regulate the fluid pressure for the particular engagement element, and a selector valve arranged to connect the second pressure chamber with the pressure control valve at a first valve position, and to disconnect the second pressure chamber from the pressure control valve at a second valve position. A shift control section is configured to command a shift operation from a first gear position, to a second gear position, by controlling the selector valve to the second valve position and to supply the fluid pressure to the first pressure chamber, and to judge the selector valve to be in an abnormal state, in accordance with a parameter in the shift operation.

Abstract: An automatic transmission includes a plurality of planetary gears disposed between an input shaft and an output shaft and having a plurality of rotational elements. A plurality of frictional elements are selectively engaged and released for controlling rotations and connections of the plurality of rotational elements in accordance with instructions so as to realize a plurality of gear positions. A rotational speed detecting section detects a rotational speed of a predetermined one of the plurality of rotational elements other than the input shaft and the output shaft. A frictional element release section releases all of the plurality of frictional elements when it is judged that the rotational speed of the predetermined one of the plurality of rotational elements is higher than a predetermined rotational speed.

Abstract: A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque-transmitting devices. Further, a hydraulic fluid control circuit is provided for controlling the operation of the plurality of torque-transmitting devices. The hydraulic fluid control circuit receives pressurized hydraulic fluid from an off-axis hydraulic fluid pump and has a plurality of fluid passages disposed in the transmission house, input member and other coupling members.

Abstract: A method for operation of a drivetrain including a drive motor and an automatic transmission having at least five shift elements, of which, at least three shift elements are engaged in each forward and reverse gear and the other shift elements are disengaged. Two successive shifts are accomplished by two overlapped single gear shifts such that a) during the first shift, a first shift element is engaged or disengaged while a second shift element is disengaged or engaged; b) during the first shift, second and third shift elements are prepared for either engagement or disengagement, and c) during the first and the second shifts at least one fourth shift element is kept engaged or nearly engaged.

Abstract: An automatic transmission for a vehicle includes a main box controlled using a series of clutches, and an underdrive assembly controlled using a series of clutches and at least one overrunning clutch. In achieving a double-swap downshift from a first transmission “gear” employing a first main box clutch and a first underdrive assembly clutch, to a second transmission “gear” employing a second main box clutch and a second underdrive assembly clutch, a controller delays release of the first main box clutch until after the second underdrive assembly clutch has been prefilled, and fully applies the second underdrive assembly clutch only after slip has been detected in both the main box and the underdrive assembly. Additionally, the controller fully applies the second main box clutch only after the second underdrive assembly clutch has itself been fully applied.

Abstract: An ECT_ECU of the present invention executes a program including the step of setting a determination time T for determining the completion of an upshift in an accelerator off mode to a short determination time T (X) when a slip value NS (NS=NE?NT) between an engine revolution NE and a turbine revolution NT is smaller than a predetermined slip value NS (0) (when the difference between NT and NE is large, and the step of setting the determination time T to a long determination time T (Y) when the slip value NS (NS=NE?NT) is larger than the predetermined slip value NS (0) (when the difference between NT and NE is small).

Abstract: An automatic transmission controller has an electronic control circuit, an electromagnetic valve, and a pressure control valve. The electronic control circuit generates a control current. The electromagnetic valve regulates a command pressure in accordance with the control current. The pressure control valve has a spool and is formed with a spool hole. The spool reciprocates in the spool hole in accordance with the command pressure to regulate a pressure supplied to a friction element of an automatic transmission. In a standby state, when the friction element is in a disengaged state, the electronic control circuit generates an oscillating current as the control current so that the electromagnetic valve generates a standby command pressure that makes the spool reciprocate in a range in which no pressure is supplied to the friction element.

Abstract: A brake band shifting mechanism for an automatic transmission. The brake band shifting mechanism includes a brake band encircling a brake drum of the transmission. A first end of the brake band is mounted to a secured portion of the transmission by a first linkage and a second end of the brake band is mounted to a two-stage servo by a second linkage. The servo provides selective apply and release pressure to the second linkage to control the compression or expansion of the brake band. In operation, the brake band is quickly compressed to the brake drum during the first stage of the servo, and then fine adjustments are made to control the speed of the brake drum during the second stage of the servo, where inputs from position and speed sensors in the transmission are used to control the adjustment of the brake band.

Abstract: A shift control system for an automatic transmission wherein shifting from a first gear ratio to a second gear ratio is carried out by releasing the hydraulic pressure of a first friction engaging element for disengagement thereof and supplying the hydraulic pressure to a second friction engaging element for engagement thereof, the hydraulic pressure to the second friction engaging element being subjected to feedback control, wherein the shift control system includes a sensor for sensing a parameter on a vehicle cruising condition; and an ECU having a part for calculating, in accordance with the sensed parameter, a difference in output-side rotational speed of the fluid coupling before and after the shifting; and a part for setting, when the shifting is carried out with an output of the engine being smaller than a predetermined value, the second hydraulic pressure in accordance with the calculated difference immediately before start of the feedback control.

Abstract: According to an aspect of the present invention, an automatic transmission includes plural friction engaging elements configures plural shift ranges based on combinations of each friction engaging element being in engaging or disengaging condition, a controlling unit for controlling the friction engaging elements to be in engaging or disengaging condition by controlling a hydraulic pressure applied.

Abstract: Each control portion for controlling each friction element includes a switch valve and pressure control valve such that hydraulic pressure supplied to the friction element is fully controlled, and a control portion for controlling a friction element that is operated both at low and high speeds includes a switch valve that senses an operation of a friction member cooperatively with the friction element at the high speed such that the friction member receives different hydraulic pressure at low and high speeds. A plurality of fail-safe valves is included for enhancement of a fail-safe function of an automatic transmission.

Abstract: The invention relates to a method for up-shifting of an automatic or semiautomatic gearbox which is connected to an engine equipped with an additional engine brake, which method comprises determining an expected value of the speed derivative (ESGe) of said engine during said gear-shifting. The invention is characterized in that said method comprises measuring the speed derivative (ESGm) of the engine during said gear-shifting (21), calculation of a difference value which corresponds to the difference between the measured value of the speed derivative (ESGm) and the expected value of the speed derivative (ESGe), and updating the expected value of the speed derivative (ESGe) to a new value which more closely corresponds to said measured value of the speed derivative (ESGm) if said difference value exceeds a predetermined threshold value (x). The invention also relates to a device for such engine braking.

Abstract: An automatic transmission achieves a desired shift through an initial stage shift in which a first engagement element is released and a third engagement element is engaged, and a final stage shift in which a second engagement element is released and a fourth engagement element is engaged. A control apparatus sets an estimated rotation acceleration for a transmission input shaft in accordance with an input torque and an input torque rotation acceleration speed, and controls the release of the second engagement element for moving to the final stage shift according to the estimated rotation acceleration. As a result, it is possible to prevent a shifting delay and/or degradation that occurs between the initial stage and the latter stage by continuous transmission of the input rotation (engine rotation) change when moving from the initial stage to the later stage.

Abstract: Although there are various combinations of engine speed and transmission state that correspond to a selected vehicle speed and load, there is one combination that best achieves a predetermined criteria. The present invention relates to a vehicle including a control system that electronically controls engine speed and transmission state in order to best achieve the predetermined criteria, such as fuel economy. There is an electronic control module including a power train algorithm that is in control communication with the transmission and the engine. The predetermined criteria is achieved by establishing a limited engine speed range that is less than an entire engine speed range, and restricting engine speed, via the power train algorithm, to the limited engine speed range. The power train algorithm is also operable to determine a combination of the engine speed, within the limited engine speed range, and transmission state that corresponds to a selected vehicle speed and the predetermined criteria.

Abstract: An automatic transmission is controlled by using a hydraulic circuit employing a mechanical pump driven by an engine, a motor pump, and oil passages to which the mechanical pump and the motor pump supply a fluid. More specifically, when a change of state in the automatic transmission and the hydraulic circuit is detected, while the engine is revolving without any aid of a starter so that the mechanical pump supplies the fluid to the oil passages, the motor pump is driven.

Abstract: A primary shift portion has a first predetermined speed ratio at a first shift-speed, a second predetermined speed ratio at a second shift-speed, a speed ratio of “1” at third and fifth shift-speeds, and a third predetermined speed ratio at fourth and sixth shift-speeds. A secondary shift portion has a predetermined reduction speed ratio at first, second, third, and fourth shift-speeds, and a speed ratio of “1” at fifth and sixth shift-speeds. The method realizes a 6-speed automatic transmission being capable of sequentially up- and down-shifting and a plurality of skip shifts with an existing 5-speed automatic transmission.

Abstract: The present invention describes a method and a device for determining the direction towards which an input shaft rotation speed changes along with the release of a friction engagement element during transmission operation, and based on the direction of change, determining whether the transmission operation is a power-on state transmission operation or a power-off state transmission operation, and based on the result of determination, deciding either the release-side friction engagement element or the connection-side friction engagement element as the main object of control for performing the transmission operation.

Abstract: In an automatic transmission, transient control of the working oil pressures for friction elements whose state is to be switched is normally carried out in accordance with a degree of shift development determined based on at least a vehicle speed. When the vehicle speed is too low to provide determination of the degree of shift development, transient control of the working oil pressures for the friction elements is carried out in accordance with elapsed time from shift instead of normal transient control.

Abstract: An output bearing assembly of a transmission includes a housing, and a pair of bearings. At least one speedometer sensor is mounted between the bearings. The arrangement allows the output bearings to be spaced axially by a relatively great distance.

Abstract: Torque phase detecting means 110 detects the starting point of a torque phase in an automatic transmission. Racing detecting means 120 detects a racing. Control means 140 shifts disconnecting or connecting hydraulic pressure or timing in the next automatic transmission according to whether the racing means 120 occurred before or after the starting point of a torque phase detected by said torque phase detecting means 110. An automatic transmission control unit which suppresses racing without giving any shock to the driver can be obtained.

Abstract: A control device of an automatic transmission has automatic shift ranges and manual setting ranges including a first speed gear position at which an engine brake is operable. The control device turns on all solenoid valves at the first speed gear position in the automatic shift driving range, turns on only the second and third solenoid valves at the first speed gear position in the manual setting range, and turns on at least one of the three solenoid valves in normal operation. This prevents a shock resulting from a shift and easily starts a vehicle even if all of the three solenoid valves supplying oil pressure to the first through third shift valves for changing gear positions are turned off. Oil channels are preset in such a manner as to achieve a high speed gear position if no oil pressure is supplied to all shift valves.

Abstract: A hydraulic control system for an automatic transmission includes a first clutch acting as an input element at first, second, and third forward speed ranges, a second clutch acting as the input element at third and fourth forward speed ranges, a third clutch acting as the input element at an R range, a fourth clutch operating at P, R, N, and L range for performing an engine brake function by stopping a one-way clutch at the first, second, and third forward speed ranges, a first brake acting as a response element at the P, R, N, and L ranges, a second brake acting as a response element at second and fourth forward speed ranges, a first switch valve for distributing hydraulic pressure controlled by a first solenoid valve to a damper clutch in a torque converter and to clutch control valves for the first clutch, and a second switch valve for distributing hydraulic pressure controlled by a second solenoid valve to the second clutch and the first brake.

Abstract: A power transmission includes a plurality of torque transmitting mechanisms controlled by an electro-hydraulic control system to provide a reverse drive ratio, a neutral condition and a plurality of forward drive ratios. The electro-hydraulic control has three shift valves, two variable pressure control valves, and a manual control valve. Each of the shift valves have a hydraulically on position, established by a respective solenoid valve, and a hydraulically off position, established by a spring. The manual control valve is moveable to a neutral condition, a reverse drive condition and a forward drive condition. In each of the positions during a neutral to reverse, neutral to forward, or forward/reverse interchange, the shift valves are conditioned to be hydraulically on thereby permitting the manual control valve to be the controlling valve member for completing the interchange.

Abstract: An automatic control for operating an engine retarder, service brakes, and an automatic transmission associated with earth moving equipment is provided. The automatic control monitors engine speed and responsively produces control signals to maintain engine speed within predetermined limits.

Abstract: A rotational direction of a rotational element at a high speed gear stage is different from a operational direction of a reaction torque at a low speed gear stage. The rotation by the reaction torque at the low speed gear stage is stopped with a self-energizing operation of a band brake operated by a hydraulic servo. A waiting pressure, which is lower for a predetermined amount than a engagement pressure at the self-energizing operation, and with which a basis of a racing amount occurs after a synchronizing point, is applied to the hydraulic servo until the synchronization is determined. The waiting pressure increases to the engagement pressure after determining the synchronization so that the rotational element is stopped gradually as preventing a long shift time.

Abstract: A line pressure control apparatus of an automatic transmission controls the line pressure of the automatic transmission under a lockup condition to ensure an engagement capacity and an amount of lubrication oil for an engaged friction element under a high vehicle speed condition. The line pressure control apparatus comprises a line pressure lowering section, a vehicle speed deciding section and a pressure changing section. The pressure lowering section lowers a line pressure under a lockup condition of the automatic transmission. The vehicle speed deciding section decides whether a vehicle speed of the automotive vehicle is higher than a predetermined value. The pressure changing section changes the line pressure under the lockup condition from the lowered line pressure to a line pressure under a normal condition when the vehicle speed is higher than the predetermined value.

Abstract: A power transmission has an electro-hydraulic control for selectively establishing a plurality of clutches and brakes for controlling a plurality of planetary gearsets to establish the transmission drive ratios. During a vehicle stopped condition, two brakes are engaged to restrain rotation of two members of one of the planetary gear sets. This results in braking of the transmission output shaft.

Abstract: A shift control apparatus for an automatic transmission for a vehicle wherein D-N-D in-gear shifts are carried out quickly without any shift shock. Engagement-actuation control for a frictionally engaging element to establish a D range when a shift is made from a N range to the D range comprises a plurality of control stages, for example, an invalid-stroke clearing stage, an intermediate-pressure retaining stage, a feedback stage, etc. When the shift to the D range is made following a shift from the D range to the N range, a shift control apparatus detects the engagement condition of the the frictionally engaging element for establishing the D range, selects one of the control stages in correspondence with the engagement condition, and initiates the engagement-actuation control for the frictionally engaging element from the control stage selected.

Abstract: A mechanical transmission for drive wheels, especially for mobile work machines, has a sprocket keyed on a drive shaft rotatably supported to a frame, an internally-cogged crown connected to a hub of a drive wheel of a work machine, and at least one intermediate gear wheel coupled to the sprocket and the crown and rotatably supported by an intermediate member. Two gear couplings are provided, each of which is equipped with own externally-activated means for command. The gear couplings connect the intermediate member with the frame and the drive shaft.