Abstract: A four-wheel drive vehicle with free wheels having free wheel hub mechanisms which utilize intake pipe negative pressure which is kept from being in the negative pressure state for a long time to diminish loading of the sealing members and improve the durability of the free wheel hub mechanisms. In the free wheel hub mechanism, a negative pressure change-over valve is disposed in an intake pipe negative pressure introducing passage to not only open or close the passage but also open it to the atmosphere. A timer is also provided to operate the negative pressure change-over valve so that the negative pressure introducing passage is opened to the atmosphere after lapse of a certain time from when a transfer switches over to two- or four-wheel drive until when the intake pipe negative pressure becomes constant.

Abstract: A vehicle theft-prevention device which includes an ignition key having a transponder, a coil unit for supplying power to the transponder when the ignition key is inserted into the coil unit and then turned to a starting position thereby permitting the transponder to generate an identification code. The coil unit outputs the identification code to a disabling controller and the disabling controller outputs an engine drive signal when the identification code from the coil unit is valid and outputs an engine stop signal when the identification code is invalid. The vehicle theft prevention device also includes an engine controller for permitting an engine starting operation to continue when the engine drive signal is input into the engine controller from the disabling controller within a predetermined communication time period from a moment the engine starting operation is initiated by turning the ignition key to the start position.