The paper is dedicated to design and test of a new dog-clutch gearshift mechanism for passenger car gearboxes with external synchronisation. There are two main targets of presented work: 1) Replace the standard synchroniser with cheap and compact shift device, which will allow the internal architecture of gearbox similar to the classical manual transmission 2) Keep all important functions of synchroniser; just not the synchronisation: minimal circular backlash to avoid clash during change of sense of the torque flow, prevent unwanted diengagement, guarantee the shift anytime. Czech Technical University in Prague is for several years active in the field of design and testing of shift mechanisms, aswel as in design of new shift cluthes. The new dog clutch is 3rd generation. All clutches were fabricated as prototype and tested. Äll designs will be briefly described in the paper. New design is simplified with respect to previous ones. To observe the real life function the prototype was assembled into the passenger car gearbox between the IIIrd and IVth speed. The transmission was equipped with external synchronization device. The gearshift tests were conducted on the flywheel test stand equipped with pneumatic shift robot. With help of external synchronisation device the different relative speeds between the freerotating wheel and shaft were preset. The impact of speed difference on shift smoothness was evaluated with help of vibration measurement. The results were compared with the same gearbox equipped with classical synchroniser and results of previously designed dog clutches. The newly invented clutch offers good possibility to minimise the number of pieces, shorten the length and lower the weight of shift clutch with respect to the synchroniser.