[mman1506]

Here is one that one of our team member built http://www.chiefdelphi.com/media/photos/24580

Its a dog shifting design, you can see the the dog in the pictures.

I could get more pictures if you would like. Basically both the gears spin freely from the shaft and the dog is attached to the drive shaft. The dog will latch onto the first or second gear transmitting that power to the driveshaft