We have a 2010 Mazda 3I sport. The transmission was completely replaced a little over 2 years ago, including the TCM. In the last 3-4 months the TCM has been replaced 3 times. Granted, we've only had to pay once. The shop has replaced the valve body and all the shifter solenoids during this issue. They have told us this and that has also been looked at including the wiring harness. I'm at wits end. The warranty is through this shop. I really believe they are doing all they can. They are a reputable shop and have been in business for 30 plus years. What do I/they need to look at? Does the main computer influence the TCM? I have no idea where to start. Any help or advice will be greatly appreciated.