Need Opinions - Transmission Issue

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mattc95

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Mar 13, 2021
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Hi All. Experiencing some trans issues. I drive a 97 Z71 with what I believe to be the original transmission. During my normal daily driving 10 minutes to work under 55mph I have no issues really. Say I have to run errands around town with a lot of stop and go, highway on and off ramps, stoplights, having to get on the gas to merge traffic etc. I begin to have issues. The trans will begin to shift hard through each early gear with a jolt I can feel in the cab as I accelerate. The truck seems to drive fine the next day until I have to push it hard again. I recently had to change multiple freeze plugs so I had to unbolt the trans and replace the fluid and coolant in that process. Trans still does the same jolt when changing gears after hard highway use. Any recommendations outside of the obvious of getting a new or refurbished trans? anyone experienced similar issue? Thanks
 

JOHNGAAA1

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Did you check the throttle position sensor ? If it is bad it will give you a hard 1 - 2 shift.
 

Schurkey

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Connect a scan tool, look for "codes", but also look at the transmission shift adaptations, trans temperature, verify torque converter clutch operation, etc.

As usual, "codes" can be helpful, but the real story is in the data stream.
 

anthony112091

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I'm having the same issue but I have a 97 suburban k1500 but I do see a p1870 at times after hard highway use after I changed my fluid I don't get the code anymore but still get hard shifts on longer drives, my scan tool won't read Trans or see live data on it I can see all of that on motor though any recommendations on a budget friendly scanner that could read the transmission I been looking lately and too much false advertising to pull the trigger not knowing if it will work and allow me to see the data needed for this fix
 
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