2006 Mazda3 stuck in 3rd with code P2709

Hi everyone. I have a 2006 mazda 3 2.3lt Automatic
The car has been acting out lately, heres what happened.
It all started with the car doing rough shifts, it would do it more noticebly when going from 1st to 2nd and when putting it in reverse. The shifts where also delayed. M mode was not displaying the gears, nor was it working. Both modes where having the same symtoms. I bought the car used and was not aware that the tcm had already been repaired. When i found out about the the tcm, i sent it somewhere to have it re-built. That did not work as it made the problems worse. When i installed the "rebuilt" TCM i had all the symtoms i used to have plus some new ones. New symptoms where; The gear selector was not lit (sometimes it would light up and sometimes not. In addition when i put the car in P it would show that i was in reverse, but i was in park, so the gear selector was off, due to the TCM. Another thing is that Reverse sometimes would work and sometimes it woulnt. Now i got another TCM (used one) And the gear selector is working but the car is stuck in 3rd gear. Its stuck in 3rd gear with both TCM. With the new TCM the car sometimes it works right for a couple of seconds but then goes back.
The mechanic scanned the car and got codes for faulty solenoid A aswell as faulty oil temp sensor. Both things where replaced for new ones. That was with the old TCM. Now he scanned it again and got a code for faulty shift solenoid 7. This time he tried another solenoid first with no luck as the car was still displaying the AT light, next he swichted the whole valve body and still got the same code for a bad solenoid 7.
Has anyone else had this problem? do you guys think it is the TCM?

The Code its putting out is P2709
2010 Mazda 5 Sport
I wonder if you have a short in the harness or a bad ground. I think you're on the right path in regards to the TCM as this sounds like something I've read here before being solved by a rebuilt TCM.

I'm no help I'm afraid.
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Sounds like the TCM. Note that not all TCM's can be repaired, used is a crap shoot. I had to buy a new one. But, before you do that, has trans fluid ever been changed? Most times these solenoids are quite reliable, but if fluid has not been changed for 110,000 miles, that could be an issue. But, it does sound like the TCM is toast.
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