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Chevrolet Transmission Trouble 2008

I have a 2008 Chevrolet Impala 3.5 L with auto transmission trouble. Around 60K miles, it started having a bit of a hesitation when taking off from a stop sign. This increased and sometimes the engine would rev up and the car would slam into gear. The first “remedy” was when a transmission shop that put a wearker spring on a servo motor so it wouldn’t take so much pressure. I really wanted to believe this had worked but about 3 weeks was enough to persuade me nothing had changed. At about 92K I puirchased a used transmission with about 60K miles and had it installed. It has been about 8K miles now and it is obvious that this has not solved the problem either. I took it to a diffewrent transmission shop and paid close to $100 for a diagnositic check and the thing wouldn’t act up. The problem remains intermittent and unpredictablle. A few days ago I set out across the intersection and it whirred a bit, pulled the car out into the cross traffic lanes with traffic bearing down on me and then jerked into gear as I went shooting across, tires chirping. There are no codes.

hmmm … well, it could be related the torque converter. Refer your shop to TSB 08-07-30-016A. Unless you have an Impala manufactured for export (for which that bulletin appears to apply), my guess is your replacement transmission has the same problem as the first one. It needs new clutches.

I believe that car would have the 4t65e trans, which is the same as my 05 Buick Lesabre. I’ve read quite a bit about common problems with that particular trans. Mine will sometimes not engage momentarily from a start, then bang into first. There are several possible causes for this from what I’ve read, none of which seemed to be easily repairable, unfortunately. The good news, apparently in my case, you can drive quite a while with this problem as long as it’s intermittent. My only advice is to make sure the trans fluid level is good. I’m assuming the fluid and filter were changed 8k miles ago when the used trans was installed.

Thanks George. I’ll see what I can find .

It could also be that the original problem was not the transmission and thus,still remains.

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That’s a really valid point. The throttle sensor in the accelerator was replaced at the same time as the transmission was changed. It solved a different problem, generally describes as a lack of power.

The gjuy at the first transmission shop put a scanner on it and showed me shift intervals, some of which, per him, were wacky. The pressure wasn’t high enough to set a code. I asked directly if there was something else that might send bad information to the
transmission and make it act like this. He assurred me there is not. But I still wonder.