Traction light on!

Traction light came on, system was evaluated and replaced the computer as a first effort, now I am told that the differential is going bad and because of the AWD system it cannot be rebuilt but must be replaced. $5600 cost. Value of the vehicle is 6K by Blue Book. Is there a fix outside of replacing differential or something else to look at? I am told it will be making so much noise before it fails that I will not be able to hear myself in the vehicle, as of now it is not making any noise at all!