Transmission down shifting

Tiny
BJ2
  • MEMBER
  • 2009 CHEVROLET IMPALA
  • 3.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 115,620 MILES
Around July 25, 2018, my car LT model, the transmissions started to bump after stopping and then stepping on the gas again. I thought the transmission was slipping. I did some research (ODB11 Scan) and troubleshooting (code P0842), found out I needed an Automatic Transmission Fluid Pressure Switch (TFP).

After replacing the TFP, the car drove nicely for a while. However, I notice when I get on the highway drive excessive of fifty mph and later come to a complete stop or slow down the transmission would start bumping like it was just thrown into gear (the bumps are hard ones).
It would continue to bump until I turn the car off. Then let the car cool down and then transmission would shift smoothly again.

I scan the car again and got some of the same following Codes: P0562, P0711, P0716, P0717, P0722, P0723, P0741, P0742, P0751-2, P0756-7, and P0843. Code P0842 is no longer there. I am thinking some of these codes are interchangeable, react to each other.

As long as the car is being driven carefully the gears seem to shift very smoothly. That with accelerating and re-accelerating. It does not matter how the car is driving on the highway you the same bumping with slowing down, stopping and accelerating again. It seems like the gears are lifted behind on shifting and just start to catch up when the engine has been shut down.

Could you please explain to me what could be the problem and how I could go about fixing the problem myself?

Thank you.
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Wednesday, August 8th, 2018 AT 12:36 PM

1 Reply

Tiny
KEN
  • ADMIN
Hello,

This sounds like a input shaft speed sensor has gone out or is off. I would clear the codes and then just turn the key on without starting the engine to see which ones come back. This will be the most prevalent code.

Here is a diagrams to help you see what you are in for when changing out the sensor.

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken
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Wednesday, August 8th, 2018 AT 1:48 PM

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