Rough shift issue in 2010 Corolla S - Toyota Corolla (2009 until 2018-19 “TNGA”)

Hello everyone! I am resurrecting an old topic, sort-of. I posted about this previously thinking it was a tranaxle problem, but I'm not sure it is anymore...

I have a 2010 Corolla S with 153,000 miles on it. If I am traveling down the road in overdrive doing 45+ mph, life is good. On occasion, if I need to accelerate, the kick-down from OD to third or second is occasionally met with a very hard jolt that has a very expensive feel to it. This winter, it became so bad that I took it in to the transmission shop to have it looked at. $100 and a full diagnostic with drive test later they said they couldn't replicate the issue, the fluid looked great, pressure was great, and everything appears to be running just fine. They were confident that there was a lot of life left in the transmission. I wish I could remember, but they also said they cleared a computer or module and wanted me to see if that helped. And, for a little time, it did seem to help a little. But it wasn't long before the problem returned. Just as I was thinking I should take it in again and drive with them, the weather changed from cold to warm and the problem has gone away. But I suspect it will be back in the colder weather.

This is a reputable transmission shop that does good work, so I don't doubt them that the diagnostics came back clear. But if that's the case, what else could be the problem? Downshifts, as if I was coming to a stop, are smooth - but when stopped I notice my engine hunting for a smooth idle speed between 750 and 1,000 RPM, which is kind of unusual and rough until it figures things out. It's only during kick-downs and it's hard to predict when it will happen until just before it occurs. While it is unpredictable, I can tell when it's about to happen a couple seconds before it jolts. Usually when I give more throttle, the kick-down feels "normal" and somewhat immediate. When the problem is about to occur, I give more throttle and the car doesn't accelerate or it will try to accelerate while in OD (with little success) for about three or four seconds - then all the sudden, bang, and you're in third or second. However, if I feel the hesitation and I let off the gas a little and then force the kick-down again, it's usually okay. I've had the problem occur when I need hard WOT acceleration right away and I've had it happen with lazy, barely giving gas to pass the car in front, throttle inputs.

I'm wondering if there are any ideas or suggestions on what to check or replace. I've cleaned the MAF, which was a long shot, and my throttle body is spotless. I've read it could be a catalytic converter could be plugged, a bad TPS, bad fuel pump, and bad speed sensor. But, all of of those things have costs associated with them and I would rather not guess at a fix and spend money on something unnecessary. Thank you for reading!

If clearing the computer fixes it it probably is indeed a sensor of some sort. I would think a TPS and speed sensors are most likely, but if the speed sensor was wrong, you might see speedometer issues. Did you check the fluid level yourself? Did this start after a fluid change (thinking maybe the wrong fluid?)? You may want to try just cleaning the connectors for those sensors.

Hello! Thank you for the reply. I'll give it a try! I did remove the throttle body and cleaned all the connections - I believe the TPS is built into the throttle body. However, I have not cleaned the speed sensor. I'll have to look up where that is and clean the connections.

This started prior to any fluid changes. I performed a series of drain and fills after I first noticed the problem and it continued. It's probably due for another round of drain and fills, but I don't think it will have much effect.

Thank you again for your help.

This generation has a learning transaxle logic, so if you only occasionally run it WOT, the reaction will be relatively slow. Resetting the PCM will temporarily wipe those settings, that's why it ran differently. If the fluid is good, pressures inside the valvebody and fluid lines are fine, nothing seemed amiss in the transaxle pan (excessive metal or material shavings) - then likely this is the PCM picking shift strategy based on driving patterns.

Only thing I can think of is to give it a healthy romp on the highways every once and a while, change up the driving style. See if that will help out. A 2010 with 153K miles is really nothing to this car - as long as you stay ontop of the factory recommended service. Resetting the PCM won't hurt, but will wipe previously stored settings (shift points, air fuel timing, etc.) - if you disconnect the battery to do this, instead of through a scantool - then you will also reset your radio presets (may run into the radio anti-theft, depending on the receiver model you have).

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I can endorse that. I've had a couple of adaptive transmission cars, but I also used to borrow cars a lot, and it would take around four days for the previous owner's driving habits to wear off! It'd be nice if they let you have two drivers and a reset button Not sure about the 2010 Corolla but some cars have a specific fuse to pull that resets the computer specifically.

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Hi Listoff, did you ever resolve this issue? I have a 2010 Corolla XLE with 100k+ miles that does exactly the same thing. The transmission shifts fine otherwise, but sometimes, not always, when kickdown from, say, 60 mph to pass, it sticks then downshifts hard to 2nd (?) gear, and sounds like the transmission's going to fall out of the car. I recently changed the transmission fluid, using Toyota brand WS fluid (manufacturer specified), but didn't seem to help. Thanks.