Thanks...
The Powertrax that I use is called a No Slip and its not a locker although they do make one.
This one has no clutches of any kind. Its works kind of like a sychonizer in a trans. It keeps the wheels locked together when they are the same speed. As soon as they vary then it unlocks. At first it was "notchy" but after a hundred miles or so I don't notice anything except good traction. Here is their web site. I find it excellent on the street.
http://www.powertrax.com/auto.htm
Rich Anderson from Shell Valley uses them and I took his advice and bought one. By the way Rich is a really nice guy who is a great source of info on BIG motors in Cobra's. He was the only person that I met that knew about the motor I use.
Regards,