Is there a differential lock on the 600 or 700 SP and if so is there just a switch to engage it or how does it work?? thanks

 

When you hit the button that has AWD on it it means ALL wheel drive.

 

The front wheels are only engaged when the rear slips some, but when they are engaged they are all pulling, there is no differential just hilliard type clutch assembly. You can download the parts manual on the Polaris website, there are some good diagrams for every part of the machine. I did this before I bought mine just to understand more how the Polaris AWD system works.