I bought a 2016 cx5 with 2.5 liter engine. Had a thrashed transmission when I bought it. I talked to multiple dealerships about which other years would be compatible. Some said 14-16 are compatible, some said only 16-18 are compatible. After nobody seeming to really know, I found a really good deal on a 15 out of a wrecked Cx5 with the same 2.5 liter and decided to try it. I stuck it in. Car wouldn’t start. Assumed it needed reprogrammed. Took it to Mazda. They said they can’t reprogram it because the TCM is married to another car. Would need new tcm/valve body. Not being one to trust dealers I brought it home. Due to the nature of previous transmission failure I knew my old tcm/valve body was good. I swapped it out. Car started. We put the FZ Mazda fluid in it and headed down the road. Transmission shifts flawlessly when oil is cool. When oil gets warm it starts acting up in 1st gear only. All other gears work perfectly. Shows up incorrect gear ratio code for first gear. I reset the adaptives using the manual mode but that didn’t fix it. Also it won’t shift into neutral at a stoplight like it’s supposed to. Thot maybe mazda could reprogram it now. Took it back and they said, Oh you need a new transmission! Be happy to replace it for over 7k. I brought it home again and here I am. Any advice? Are these transmissions serial number specific? Is there really no way to simply reprogram them? Thanks for any input…