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Thread: still have harsh shifting problem on my 93

  1. #1
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    still have harsh shifting problem on my 93

    93 1500, 5.7, 4L60E...harsh shifting from park to reverse and drive, sometimes on 1-2 shift, rest are ok. history: truck went into trans shop due to free reving rpm increase on mild acceleration onto freeway in I blieve 3rd gear...all solenoid replaced--three times, no joy. finally shop replaced ecm with OEM brand from autozone and that problem went away......now came the harsh shifting issues so all solenoids were changed, three different times, I saw valve body down twice and still no joy. I myself replaced a broke temp sensor on top of intake, broke vac line of some type that went to the MAP ( not sure when or how these were damaged) and finally the TPS which seemed to significantly help the harsh shifts EXCEPT for the park to reverse and drive and this is intermittent and most noticable when truck has been turned off and sits. example going thru fast food drive thru and turning off truck and putting into park for couple minutes or when starting after work or overnight. Help.....could the ecm be defective or is it one or all of solenoids or ?????????? thanks for advice.

  2. #2
    Senior Moderator chevychase's Avatar
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  3. #3
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    i would check the tps, number 26, seen it on my 90
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    Need to check the grounds, make sure they have good clean tight contact, and check wires make sure none are rubbing or shorting out, but if that happens should get a check engine light if it shorts out a sensor.
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  5. #5
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    new tps, grounds cleaned and tight, no bad wires etc. so I am at loss

  6. #6
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    Might need to check the servo. I'm not a trans man but I'm pretty sure it has something to do with shift pressures.

  7. #7
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    all solenoids/servos changed before, 90% of time still get harsh shift from park into reverse or drive, quick but firm on other shifts except 40% or so the 1-2 shift is harsh.....still searching for some kind of solution as trans shop can't figure it out. I am afraid a hard part will brake and on top of that it is really annoying and ticks me off.

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