Ive tried doing some searching, but havent found the answer to my problem. Truck is an 07 LBZ. I am wanting to change some of the TCM tables and I cannot get efi to read the stock calibration with V7.5 but I can get it to read the calibration with V8. But in V8, it saves the file as a .ctz file and I cannot open or save it as a .ctd file for modification in V7.5. With V7.5, it will get to "Initializing TCM", and then not go any further until I press stop. Anyone else run into this problem? I have all the latest updates and still a no go. Any help is appreciated.