[Maxx42]

It sounds like it is fried. Does it still run? Even if it does you will probably have to send it in for repair soon. I don't think that the nylon stocking had much affect on the esc smoking. Running in sand (especially with paddle tires) will put a lot more stress on your esc. If you use this set up in the future, it may be wise to use smaller pinion gears to give the motors some more torque advantage in the sand (they would draw less current that way too).