Got under and looked. Definately covered with crap. Gear oil is more like it. Lots of gear oil. Didn't get a chance to clean it up good, but is there a plug where this mounts? Looks like it is leaking where the sensor is. By the way, this wouldn't be covered under drivetrain, would it?

 

Maybe you can get "really" lucky and take the sensor out, spray it with some CRC electronics cleaner and pop it back in.

 

My extended warranty would have covered it, but since I only had the truck for a month, the dealership ate the cost.