On the Mazda 3, 5, and 6, if it is having the issue of not getting out of 3rd it will most likely read a bad solenoid. Even if you replace all of them on the transmission, you still have the chance it will not fix the problem. Instead of replacing the transmission, switch out the TCM, (transmission control module) and see if that doesn't fix your problem. Should shift as smooth a silk. Also another thing to check with that problem would be the speed control sensor.