Abstract: A drive system for a tractor which is operable in either a two wheel or a four wheel mode of operation. The drive system includes a control apparatus which automatically establishes a drive connection between a power source on the tractor and a front pair of tractor wheels through regulated operation of a normally engaged clutch assembly in response to application of service brakes on the tractor. Thus, the decreasing inertia of the power source, inherent with deceleration due to braking, is utilized to substantially equalize wheel slippage between front and rear pairs of wheels thereby advantageously improving braking performance especially as the tractor operates at relatively high speeds.

Abstract: An electronic powershift control system for an implement transmission having a plurality of selectively operated electrically controlled hydraulic powershift clutches. The system includes a manually positionable gear selector connected to electrical control circuitry. The electrical control circuitry receives input shift signals from the gear selector indicative of the shift desired and, in response, produces output shift signals for operating various hydraulic powershift clutches over a predetermined time to effect the desired shift. The electrical circuitry further incorporates a feed back loop which allows the circuitry to monitor shift performance effected during the desired shift and, if necessary, adjust the predetermined time of powershift clutch operation the next time the same shift is selected by the operator.

Abstract: A rotatable shift lever for selectively shifting a vehicle transmission by rotating the shift lever handle and pivoting the lever to selectively engage the desired gear ratio of the transmission.

Abstract: A locking link for locking the articulating joint on an articulating vehicle. The link has a locking position which locks the articulating joint on the vehicle and a rest position where the link is in a vertical rest position carried on only one of the bogies of an articulating vehicle.

Abstract: A hydraulic control system including a plurality of individual clutch valves for selective operation for controlling clutches in a power shift transmission. A modulating valve and a clutch valve release mechanism are included for modulating the clutch engaging pressure and the clutch disengaging pressure automatically. A single source of pressurized fluid provides pressurized fluid for operating the hydraulic actuators through the clutch valves and pressurized fluid to lubricate the power shift transmission having wet clutches which operate in hydraulic fluid.

Abstract: A valve assembly for a power shift transmission with a valve body and valve cover integrally mounted on the transmission housing. The valve body includes flow control valves while the valve cover includes pressure control valves for regulating and modulating fluid pressure supplied through the valve assembly to hydraulic fluid clutch actuators in the power shift transmission.

Abstract: A power shift transmission mounted within the transmission housing and a hydraulic system for operating the transmission. The housing has an opening for receiving a transmission control unit. The opening provides an inspection window when the control unit is removed. The transmission and control unit are equipped with internal plumbing and a provision for automatic coupling of the control unit with the transmission when it is assembled on a transmission housing. The control unit is constructed such that it can be replaced by an identical unit for convenience in servicing with a minimum of downtime.