I have a '74 Chevelle with a TH350 automatic transmission from a '66 Chevelle. In my fuse block, there's a fuse for the Radio, accessories, TCS, and "Turbo-Hydramatic Downshift." The fuse has been blown for a couple weeks, with no noticable change. Obviously, it's not making my transmission downshift, so assumably never was. I'm wondering what the hell this is, and what the TCS is also. Anyone can help me?