TPS in a 4L80E...

Discussion in 'Chevy Truck Forum' started by HankFerl, Mar 14, 2010.

  1. HankFerl

    HankFerl Member

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    I have been researching my problem with my tranny in my truck and I think I have it narrowed down to a faulty TPS or an Imput Speed Sensor. I have a 99 Chevy Suburban 2500 454 4X4 with a 4L80E. HARD shift from first to second. I know the TPS is located next to the Valve Body and the Imput Speed Sensor is on the outside of the tranny about 8 in from the bellhousing. Can anyone help me with locating them and how to replace them? Thanks!
     
  2. bradrhale

    bradrhale Senior Member

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  3. HankFerl

    HankFerl Member

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    I called and Autozone carries the TPS and it is about 35 bucks, not too bad, sure beats replacing the whole Tranny! We will be taking care of it soon. Where is the TPS located do you know?
     
  4. HankFerl

    HankFerl Member

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    I just looked at the link you showed. The connection is a little loose, but not bad. I will try replacing that. If not do you know where the Imput Speed Sensor is? I just can't believe that something that far from the tranny would make it act up that way!
     
  5. bradrhale

    bradrhale Senior Member

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    remember that you have an electronically controlled trans. everything that it does is controlled by the PCM. the PCM gets all of its readings from all over your truck. i would test the part out before replacing it. 35 might not seem much but it stacks up when you still dont fix the problem. usually a TPS problem will register a Service Engine Soon light. as for the input speed sensor, it should be located sonewhere close to the bellhousing like you mentioned earlier. the output shaft speed sensor will be located towards the back end on the output shaft. the PCM takes reading on both input and output shaft speed of the tranny and that too, controls certain things.
     
  6. Bigg G

    Bigg G Full Member

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    #6 Bigg G, Mar 15, 2010
    Last edited: Mar 15, 2010
    I have the same issue with my 95 Silvy but I changed the Coolant Temp. Sensor and T.P.S. and that seemed to have helped to make my 1st - 2nd shifts firmer sometimes but not always.
     
  7. HankFerl

    HankFerl Member

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    Well I replaced the TPS today and nada... Dang it! What next? We just passed Emissions this last weekend, if the PCM was bad that should have shown up at emissions. I am just at a stand still. Any other suggestions?
     
  8. crabtruck

    crabtruck Senior Member

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