Shifting problem

1995 PONTIAC GRAND PRIX
181,231 MILES • 3.1L • 6 CYL • AUTOMATIC
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DOUG MCCLUSKEY
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When i drive my car it will not shift into overdrive. But after a few miles i can stop and shut it off, then restart and drive again and it will shift properly.
Nov 18, 2017 at 7:03 PM
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JACOBANDNICKOLAS
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1995 was the first year for the OBD 2 diagnostic system. With that in mind, has the check engine light ever come when this happens?
Nov 18, 2017 at 9:12 PM
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DOUG MCCLUSKEY
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Sometimes it will. And sometimes not. I have had it plugged in but it has shown nothing.
Nov 19, 2017 at 2:47 PM
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JACOBANDNICKOLAS
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Do you have a scanner that will read transmission codes? Most inexpensive ones won't.
Nov 19, 2017 at 4:49 PM
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DOUG MCCLUSKEY
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O'Reilly has tried but nothing.
Nov 19, 2017 at 5:01 PM
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JACOBANDNICKOLAS
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Usually, the parts stores only have scanners that will read engine codes. With that in mind, confirm with them that they had one that will.
Nov 19, 2017 at 6:07 PM
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DOUG MCCLUSKEY
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Ok i will ask them. But in your opinion is this a possible chance of jyst a short somewere
Nov 19, 2017 at 6:10 PM
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STRAILER
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To me it sounds like you have ECM that is going out becasue when you reset the system it starts working again. Have you serviced the transmission lately?

Here is a guide to give you an idea of what you are in for when doing the job.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Also here is the location of the ECM I would try to get a used one and plug it in to see if this is the problem.

Please let us know what happens.

Cheers, Ken
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Nov 22, 2017 at 11:22 AM