I have a 2008 Chevy Aveo LS, automatic. Vin number KL1TJ62Y38B117109, engine number F15S3224691K. The automatic transmission changes gear down and up repeatedly, especially when cold. This problem began gradually, and has become worse and worse over the past few months. When it started, it only seemed to happen when the car was still cold. Now, it happens all the time, though slightly less severely when warm. I have changed the transmission fluid (using the recommended Dextron 3), but it didn't help. (Changed, not flushed. About half the old fluid remained). Fluid level is correct. I have checked for OBD codes, but nothing shows on the device I used. I'm guessing that this car doesn't have sensors for the transmission.
Mileage?
87000 miles
Scotty is right you know..
If you’re hell bent on fixing it, find a transmission specialist and have them diagnose what’s going on.
Those little cars they're not even Chevrolet they're built overseas somewhere. And your transmission is just going out it's typical for those things that kind of throw away cars. Get the price on a rebuilt transmission you'll probably junk it now we're just driving till it doesn't move anymore then junk it
I really need to try to fix this car, rather than just run it into the ground. Can anyone suggest what component inthe transmission is likely to be causing the problem?
Probably the person here who would be most familiar with that transmission is @dan. Maybe he'll have some suggestions when he checks in to the board.
I'd really appreciate that. I know it is a junk car. But it is otherwise in good condition, and cars are very expensive in this part of the world. (Not the US.)
Since I invoked his handle, he should be notified when he logs in so hopefully he will chime in. In the meantime if you have not done so already you might want to search topics and/or inquire on an Aveo enthusiast site.
https://chevyforum.org/chevy-forums/forums/chevy-aveo-forum.2/
https://chevroletforum.com/forum/sonic-aveo-11/
https://forums.edmunds.com/discussion/14025/chevrolet/aveo/chevrolet-aveo-maintenance-and-repair
@ChuckTobias - Scotty said everything I had to say.
I haven't seen eradicating shifting like this, but I can give general info and tips.
The Chevrolet Aveo (T200 and also the T250 as far as I know) uses an Aisin 4 speed automatic transmission - the only good part in an Aveo. The Toyota U440E (GM calls it AW80-40LE either gen 1 or gen 2, although I'm seeing it mostly being referred to as AW81-40LE/AW80-40LS/AW81-40LS) - The same line of Aisin transmissions as used by the '00-'07 Corolla. But swap transmissions only from the same brand, and better if that's the same year, engine size and body style.
I have no clue if it's actually shifting or if it's randomly and erratically shifting - This late production usually they're reliable, all issues you see on them is just mechanical wear or bad oil changes. It might be torque convertor lockup, or solenoid issues - but it's not the kind of things you replace on an Aveo - the labor probably costs more then that badge engineered Korean DAEWOO.
Here's a quick but extraordinarily detailed video on this transmission - use subtitles for English.
If you are sure that the rest of the car is alright - I'd try to find a junkyard tranny.
But genuinely? I'd junk the Aveo they are nightmares once they begin to fall apart.
It occurs to me that I never reported back on how I resolved this issue. In the end, I identified the transmission fluid temperature (TFT) sensor as the most likely culprit. Tested it using multi-meter, comparing the readings to the spec readings in the factory manual (which I found online somewhere). Sourced a replacement from a scrapyard, and the car has been running like a dream ever since.
I'm grateful for the feedback of contributors @ChuckTobias and @dan. But I must say, the single most unhelpful reply I received was Scotty's (saying that because the car is junk, I should just drive it into the ground - or words to that effect.)
@andrezar Thank you for letting us know about your successful repair, that becomes part of the searchable data available here for future reference. I cannot speak for Scotty but he was probably replying from the standpoint of U.S. ownership where those cars are considered disposable.