Replacing a 4 speed auto transmission in 07 Aveo

[dbooyah93]

My wife has gingerly cared for and driven her 07 and loves it dearly.

200k miles is upon us and we have replaced all suspension parts, the break hoses and calipers, valve cover gasket, transmission filter, and battery terminals. Maybe more, but the point is that the body, frame, suspension and most of the engine is in great condition. Starts up and sounds nice and we've always been on top of the oil changes as well as the previous owner.

The only issue is that the transmission fluid is black and even after a filter change the car lugs and has issues shifting when she drives more than a half hour.

We are going to buy a manufacturer rebuild from the near by Chevy dealership for $2,500 if we can read about how to swap the transmission. We have a PDF manual, but I haven't had much time to look since we've made this decision.

Does anyone have advice/experience to help guide us?

[avguy]

I would not replace the transmission simply based on the 2 symptoms you described, because neither of them eliminates the engine as being the problem. And black fluid does not indicate transmission failure, unless the fluid smells burnt, or there are metal fragments mixed in with the fluid.

At the very least I'd want to scan for codes, using a reader capable of reading the TCM. If nothing helpful comes from that, then additional diagnosis using a realtime data stream reader would be my next step.

[dbooyah93]

Thank you for your reply! Do you think the Blue Driver scan tool will be sufficient?

[avguy]

Yes that would work, but I believe Torque Pro for Android is just as good for a lot less $$.

[dbooyah93]

Do either provide live information?

[avguy]

Yes, they are both realtime OBD datastream readers.

[dbooyah93]

I found a bunch of small blue translucent modules with different names. Most are $12 does that sound right?

[avguy]

Yes, I assume you're looking at Bluetooth OBD dongles, and then you would also need to download the Torque app to your device.

[dbooyah93]

Is any dongle appropriate? They all say ELM 327, but some are large and black with lights and others like I said small and blue. Some day HH OBD2. I just don't want to buy the wrong one and have to buy and wait for another.

[avguy]

You need to compare the specs provided for the dongle, to make sure it's compatible with the device (phone, computer) you will be pairing with it and using to read the data stream.