Hello I'm new to the forum and I am in need of help. My fiance and I recently bought a used 2008 Cobalt LS and I am having transmission problems. Long story but I'll try to summarize, I took it to a mechanic and said the tranny will have to be rebuilt or replaced, he said he would have to send it out and gave an estimate of around 2500. Right now we can't afford that as we are both going to school in the fall, I have a friend who was a mechanic and suggested to just swap it with a used transmission as it will be much cheaper. I found one today that belonged to a 2010 Chevy HHR for a good price and bought it since I was told it will work for my Cobalt. I went home and did some research and while I did find some threads and people claiming it will be compatible, I also found a closed post on here with someone doing basically the same swap albeit out of choice, but was told he would have more things to do electronic wise as the gear ratios were different for each transmission. My question is will doing the plain swap work? and if so, will the different ratios have a negative effect on the car or ruin it farther? also will I HAVE to reprogram the TCM or can I just leave it as is? Thank you all for your time!