Abstract: A method and system for controlling downshifting in an automated mechanical transmission system (10) utilized on a vehicle. When an automatic power downshift from a currently engaged ratio (GR) is required, the engine acceleration (EA) is monitored and compared with an engine free acceleration (EFA) to detect a false Neutral condition and to take appropriate action accordingly. Alternatively, a false Neutral condition is detected when the Absolute Value of the rotational speed of the output shaft (OS) times the currently engaged gear ratio (GR) minus the rotational speed of the input shaft (IS) is less than a predetermined value (ABS((OS*GR)?IS)).

Abstract: A control system and method for automated mechanical transmission systems (10) of the type interpreting a first predetermined combination of parameters as a request or requirement for a direct shift to a predetermined default start ratio (GR.sub.DS) is provided. The control provides a predetermined series of actions by which the vehicle operator may manually select a new default start ratio such as, for example, by manipulation of shift selection device (1) displaceable in a first direction to select upshifts and in a second direction to select downshifts.

Abstract: A control system and method for a semi-automatic mechanical transmission system (10) is provided for allowing operator request for a direct upshift and/or downshift into a preselected start ratio, under certain predefined conditions, by a single movement, or two movements, of the shift lever (1).

Abstract: A control system and method for a semi-automatic mechanical transmission system (10) is provided for allowing operator request for a scrolling display of allowable ratios in either the upshift or downshift direction, and for a direct shift into the selected one of the displayed ratios. In one embodiment, retaining the control (1) lever in a displaced position for one or two seconds will initiate the scrolling display, while retaining the transmission engaged in the initial ratio, and subsequently release of the control lever to its centered position will cause a direct shift into the then displayed ratio.

Abstract: A control method/system is provided for controlling start from stop shifting operations of a vehicular semi-automatic transmission system (10) of the type automatically implementing selected gear changes of a mechanical change gear transmission (12) and requiring manual operation (3) of the vehicle master clutch (16) in start from stop conditions is provided. During engagement of a selected start ratio, the system controller (38) monitors for gear butt conditions and will warn the operator if such conditions are sensed.

Abstract: A method and control for controlling an AMT system (10) having an operator actuated engine compression brake (17) is provided including sensing vehicle deceleration and monitoring throttle position (THL), vehicle brake actuation (BRK) and engine compression brake (ECB) actuation to select one of three (50, 52, 54) mutually exclusive vehicle deceleration downshift shift profiles.