Parts cannon is a bad way to repair. You did not mention having any ABS issues and yet you replace them.
Is this the transmission sensor you replaced?

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Home >> Chevrolet >> 2008 >> HHR L4-2.4L >> Repair and Diagnosis >> Transmission and Drivetrain >> Automatic Transmission/Transaxle >> Transmission Speed Sensor >> Locations

Transmission Speed Sensor: Locations

Electronic Components




1 - TFP Manual Valve Position Switch Assembly
2 - 1-2 Shift Solenoid Valve
3 - 2-3 Shift Solenoid Valve
4 - Output Speed Sensor
5 - Input Speed Sensor
6 - Pressure Control Solenoid
7 - TCC Control PWM Solenoid


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I replaced the transmission speed sensor and all four hubs with wheel speed sensors

The speed sensor that mounts on the side of the transmission

Number four

 

I would be looking at the connector on the instrument panel.

 

I've scanned it and no codes, thanks for your help

 

What name code reader did you use ? Does it have the capabilities to read anti lock brakes systems ? You’ll need one that does since your symptoms seem to relate to the anti lock or powertrain system.

 

Perhaps there is a bad stepper motor in the speedometer? I had that in my Cadillac ATS, same problem.

 

Stepper motors are cheap and vary a lot. If you want to try that, Turn on the key and take a picture of the dash so you can see exactly where the needle points. Turn off the key, then remove the cluster and use a fork or something similar to pry off the needle. As I recall, the motors just twist slightly and come out. Replace the cluster without the glass, turn on the key and press the needle on gently. Make sure it points to the right spot. Weirdly it may take a few tries to get it right as most of the time I've pressed them on after carefully lining them up they've moved. If you just put them on a small amount sometimes you can move then on the shaft by gently flicking the needle with your fingernail. I've removed and replaced more GM needles than I care to think about and it's always annoying.

By vary a lot I meant, some are really well damped and others tend to have no damping at all and so the needles overshoot and bounce if you try to move them to fast. Don't know if that matters on a stock dash.