Transmission assembly comprising a main gearbox in series with countershafting providing at least two gear ratios

In a transmission assembly, in particular for an automobile vehicle, comprising:

• a gearbox comprising means providing a plurality of stepped gear ratios and a first control mechanism having a change gear lever movable to various positions for selecting and changing said ratios;
• and countershafting comprising means providing at least two gear ratios placed in series with the gearbox and a second control mechanism having a pre-selecting lever having at least two positions corresponding respectively to said gear ratios of the countershafting;
• the improvement comprising a device performing the function of a delay device adapted to retain instructions to change the gear ratio of the countershafting, which instructions result from a change in the position of said pre-selecting lever, actuating means being provided between the first control mechanism and said device for suppressing the retention of said instructions when the change gear lever is brought to a given position.