7.3 yes 4r100 he!! anyone that knows diesels knows the 4r100 is the crappiest tranny ever built when adding a chip. I personal went through 5 on my 01 and every psd I knew with a chip last the tranny soon after. These were built trannies also. Back on topic it sucks to see you have such bad luck but you actually think a opinion of one person would have that much affect on chevy there has been alot of guys with no problems, at all with them, it dont matter the make they all make some that suck and fall apart. No two trucks are the same, I would def get ride of it and invest in a new truck.