Heard of a locking differential that uses an electric magnet to lock. It's an interesting idea. Supposedly, the electromagnet is in the differential housing with only two wires coming out - no motors, no compressors or air lines.

Anybody heard of this?

Look up eaton, it is supposed to be out only for 14 and I believe 12 bolt applications. I don't think that anyone other than peterson's has gotten their hands on one though.

You are correct - it is Eaton.

http://www.traction.eaton.com/prod1.htm