How to create a vehicle with more than 4 wheels in 4.2

hi
I have created a vehicle with 10 wheels according to the documentation or the youtube tutorial,when I define 4 wheels everything is fine but when I add the 5th wheel or the next 6 wheels, vehicle won’t work at all and nothing works.
Have anybody created a more than 4 wheeled vehicle in 4.2 or other versions?
any tip or tutorial about this would be appreciated.