The only way you can do this is to use cam pairs. This is not "real contact", but it will be very close as you can enable liftoff and include friction and a coefficient of restitution. Create a cam connection between both gears. You must have straight-cut gears only, no helical gearing will work. You can use datum curves that are assembled in the sameplaneor extruded surfaces as your geometry to select as the cam curves/surfaces. This will allow you to model backlash as well. You will need to select "enable liftoff" as an option.
I hope this helps - good luck,
Kaz Z06
