I have a 2005 100 with a little over 150k miles on it. My VSC Off indicator light and Center Differential light came on when I leaving a meeting. I wasn't able to get it off. It's gotten stuck before but usally goes off after stopping and starting but this time i couldn't get the VSC Off light to go off and had to drive on the highway. It was pulling to the right but otherwise seemed normal. I was going about 65 when dark smoke started pouring out the back. I pulled over and saw differential fluid dripping out. I drove it off the highway but it was driving very rough. I don't know if i did a lot of damage by doing that and maybe should have just called a tow truck. Anyway it's at a shop that I have know idea if they are even able to fix it. It's a shop that specializes in European cars but they were only a mile or so off the highway. My question is how much should I expect to pay to replace the front differential and did I do even more damage by driving it another mile or so after the smoke and rough feel started. Is this a job that any decent mechanic should be able to handle or should I find a Toyota shop or dealer?