4l80e hard shifting

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Jul 6, 2013 | 04:19 PM

mooseknuckles

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Staging Lane

Joined: May 2010

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4l80e hard shifting

I hope someone can help..I have a 86c10 with a lq4/4l80 and after the tranny is warmed up it shifts very hard in every gear...it has always done this, its a PSI Conversions pcm and harness. I have tried switching the ISS and VSS sensors around, checked the trans harness plug, not sure what to look for?...I do not have the wire for the park/neutral ground hooked up to the neutral safety switch because mine only has the single plug for the back up lights.....it keeps throwing this code...

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Jul 7, 2013 | 10:22 PM

seventy7 caprice

Teching In

Joined: Feb 2013

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not an expert but i think thats your input speed sensor to the trans, it senses the speed the cranks spinning not the output speed. you need a real time scanner to make sure the sensor is reading correctly or reading at all. my car did the same hard shifting till i had the sensor hooked up correctly.

Jul 8, 2013 | 07:19 AM

Old Geezer

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Joined: Jun 2004

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From: GA, USA

- Faulty Transmission Speed Sensor
- Transmission Speed Sensor harness is open or shorted
- Transmission Speed Sensor circuit poor electrical connection

Some check points.............