KMD106

Hello. We are having an odd problem with our 2009 Mustang. We purchased it two years ago. Within the first six months, we had transmission problems. The OD light was blinking and it was making a horrible noise. We took it to a shop and had the transmission rebuilt. No further issues for about six months. We thought we were in the clear until we went for a drive and it started making that same noise as last time. We immediately knew it was the transmission again. This time we decided to have it towed to a very good friend that runs a transmission shop. He confirmed it was the transmission. We opted for a brand new one this time, hoping that it would resolve the issue once and for all. All good for a month. Now the OD light is blinking again. The car isn’t making any noises this time though, and it seems to be shifting fine. The only thing we have done since the new transmission is we replaced the radio a few days ago. There is also an ongoing issue with the AC that we are currently working out. Is there a possibility that the OD wire is bad? I can’t imagine how a second transmission could go bad in the last two years. Any input would be greatly appreciated. Thanks!

houtex

The light blinking means the transmission has a fault.

Um.. that's the 'duh' explanation, I'm sorry for that.

The transmission will store a code or codes in it. You'll need a scan tool that'll read the transmission to figure out what the problem is and fix it. It could be the electronics, a short, or an unexpected result of the mechanicals, such as a piston not moving to engage... lots of things. You'll just have to get it read.

The transmission going out again that quickly could be just luck in this case... or it indicates there's another issue in the car that's causing it, and finding that might be fun... It could be wiring, or something that was swapped over from the old transmission to this one...

And yes, new ones go out right away sometimes. That's why they have a warranty, otherwise, they'd never fail, and a warranty would be silly.
I'm sure that's not what you wanted to hear, but there it is. Good luck and welcome to the forums!