gearbox malfunction limited performance 2005 aro 93

the first time mi car stalled and after trying to start it, nothing, no cranking sound just lights, I had to tow the car, second time i disconnected the battery and car started normal, I used the car for 4 months and was having the stalling a gearbox malfunction error, but everytime i just disconnected the battery and started normal, until one day i left the car without driving it for more than 30 days, cas was dead, I tried to jumpstart and nothing, I replaced the battery and car started fine and after 5 minutes car died, I took the car to a mechanic shop, I paid tow truck and diagnosis 250 dollars. they could not fix it. I took it to dealer and they replaced the ECU 1015dollars total, but problem is gone!
:)

I just got the gearbox malfunction message. Been searching for 2 days straight on a possible fix. Obd code says p0720 speed sensor output. But by reading all the forums just switching this sensor isn't the fix. Anyone have luck here just replacing the sensor? Car starts and shifts like a new car till the message pops up. I have to clear the code to get it back to normal.

Sensor was the initial diagnosis of my local shop. They replaced the sensors and it worked for a few weeks. However, sensor must have been more like a leading indicator of bad things to come, because bad things certainly did come. One torque converter and two trannys later...basically I found out SAAB had redesigned the valve bodies in the tranny. Unless you get the new design valve bodies you will continue to have problems. Sensors might fix problem now, but it's more like a band aid than the cure.

So I payed only $2k for the car used. Has 112k on it. I'm guessing replace the sensor and put back up for sale. Hopefully I can make my money back.