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Discussion Starter #1
Hey guys

I got an 07 Cobalt 2.2 auto trans.

About two months ago my car started shifting hard when i went from Park to Reverse or park to drive. When it switches gears when im driving (2,3,4) the car sort of 'hiccups', worst going into 2nd and barely recognizeable going into 4th.

The car does not shift hard however when idle if the wheel is turned all the way to the right, or if im going from reverse to drive. When it does shift hard, the whole motor moves.

Like i said, it only does this when the engine has been running, on a cold start i cant feel it. Car seems to be shifting fine other than that, no grinding/slipping.

I took it to a shop and the guy said he ran a code and got a bunch of O2 sensor problems and a trans problem that if i replace the trans for 1600 all the problems will go away.

So i take it to a trans shop, the guy looks at the paper the other dude gave me said it could be the (Pressure Control Solenoid?) which is on top of the trans and that would be the fix if the code is correct, but didnt investigate further.

Im reluctant to replace the trans if the second guy is correct, and i think the first dude is trying to get me to buy an entire trans.

Just wondering if any of you had this problem before or know what it could be.

BTW, havnt replaced tranny fluid since i bought it (3 years), fuel filter is going bad which i have to have replaced, engine light is on, if any of this helps. Thanks.

EDIT: Ill also add that the shifting hardness seems to be affected by how hard i accelerate to. If the RPMS are high, it shifts fine, if i keep them low, it jerks a little, if i press down normal it shifts hard.
 

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Levee
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Sounds like the second guy is right to me. Check your motor/tranny mounts as well to make sure those are still good. When those go out they make a bunch of hard shifting.
 

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Discussion Starter #3
hey thanks for the response. my buddy said that too cause the engine moves kinda heavily when the shift happens i just didnt know if the mounts could cause a hard shift, but i guess it would seem like a hard shift if the engine moves that much lol. ill check it out and post back
 

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Levee
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Yes definately sounds like it could possibly be a mount. And welcome btw!
 

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You never mentioned the mileage, but I would tend to agree with Leveecius on a possible engine or transmission mount being all chewed up, but would like to add that if you are near 100,000 miles and have never changed the transmission fluid and filter that you should do so. About a 1000 miles before you change the oil and filter add half a bottle of transmission fix. This will clean deposits at "O" rings and solenoid armatures getting it ready for your service. Better to do this before than after to avoid dirtying your new filter.

All brand name companies make their own, but anything similar to this is good.
 

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Seafoam is a good trans cleaner too.
 

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Discussion Starter #7
Im at 110k

Never changed it cause my coworker told me it could cause the electronics to mess up and cause trans slipping.

So you guys recoommend trans cleaner then about a few days from now change the trans fluid?

If that doesnt help it ill take it in and get the mounts change, the movement feels like its under the dash towards the left center, possible trans mount?

Thanks alot for the responses btw i appreciate it
 

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I don't know about the seafoam, but the Lucas transmission fix you can actually leave in until you decide to do the maintenance service on it, but drive at least 1000 miles with it before service. You can add the other half after the service for good measure.

As far as the motor mount at the fire wall, it is usually the first one to fail. This one will let engine kinda rock side to side when you start the engine where you can actually feel it at the wheel.

 

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Can I run TransTune in my transmission fluid over the long term, instead of just before a transmission fluid change?

Yes, you can safely operate your transmission with TransTune added as directed on the can, and it will continue to help keep transmission components clean. TransTune is composed of 3 different petroleum oils, and 2 of these oils will gradually evaporate and be vented out of the transmission system.

Sea Foam | How to Use - Trans Tune

Figured I would post something and then follow it up with a link for once
 

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I have heard of gm's auto trans acting up on shifting if there are a bunch of O2 sensor codes stored, have they been cleared out ?
but I can't say that I have heard this with a cobalt.

So change the fluid and filter and like said above check the mounts.
 

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From your description and the shops diagnosis, I would suspect a band control solenoid. Any TCM codes? Or the holding band itself. Idk how the autos work in this car. But 1-2 usually applies the holding band, and 3-4 should release it if I'm not mistaken. Either way, $1600 doesn't sound horrible for the work involved in getting in there. But I would personally drop the pan and look for metal shavings, change the fluid and filter, have the oil cooler and lines flushed and see what happens.
 
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