Is the locking diff. electronically activated? If so, is there a mod to activate or deactivate it from the cab?

Mechanical activation, internal to the diff.

It is a GOV-LOC system, all mechanical as mentioned above. If you want to intervein, you can install an e-locker.

What is an e-locker? If there is already a good thread on this you can just direct me there


Thanks.

You can search e-locker and there is several threads about people ordering them and installing them. Here is a link to a supplier:
http://www.vandergear.com/E-Lockers/e-lockers.html
John Kennedy of Kennedy diesel also has a kit that does the trick. What an e-locker does is, at the flip of a switch, your rear-end will electro-mechanically enguage so that both tires connected to the locked axle will be spinning improving traction. You can get one for the rears and the fronts. They are pretty simple, just way more than I need. I hope I have been able to answer your question, if not, let me know.