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…
2016 CX-5 at all compatible with 2015?
- Thread starter on2ndthot
- Start date
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- Plano, Texas, USA
I remember when people replace the rear differential the serial number needs to be registered into the PCM. Not sure you need Mazda computer to do it or not. But IMO your replacement transmission could have issues by itself too based on your described symptoms.
You could have a few things going on. What was your original failure? Start with the basics. Is the fluid at the correct level, is the filter secure, is the valve body torqued correctly and no seals pinched? Do you have any other codes? Did the other transmission have any debris in the pan? Do you have a picture of the tag on the donor transmission and your original? If it's setting a gear ratio in 1st gear and the trans works ok until warming up that is usually indicative of a hydraulic leak or a clutch wearing and when it gets hot it can't hold correclty. Where you picked up a 15 it's also possible the unit has an issue with the Low/Reverse clutch set and one-way clutch. Does the fluid smell like it's burning? If there are any codes active the TCM will stop adaptive learning and will not let neutral idle control function.
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- Plano, Texas, USA
Thanks for quick response! Do you know if the serial number from replacement transmission needs to be programmed into the PCM (or TCM) like the rear differential? Can it only be done by Mazda computer?
Serial number does not need to be written in. They generally need to be programmed with the correct calibration for the vehicle or they may not work or let the car start because of software mismatch.
