Scoured the threads for a recent problem I'm having. Got under the truck and I have a Burned wire which has disabled my ability to use 4 wheel drive. Around this same time, the transmission seems to slip/shudder under load. Under regular conditions if driven lightly no slipping. Would this be a product of the burned wire? Tranny fluid is not burned or low. 65k miles on the truck and fairly well maintained. Also no codes.

Any help is greatly appreciated even as a starting point.