Not shifting down

2000 CHEVROLET S-10
215,000 MILES • 4.3L • V6 • 4WD • AUTOMATIC
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RJRT
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  • 7 POSTS
After the truck is warmed up when you get down to about 20 mph the truck doesn’t want to shift down to first on its own.
May 21, 2020 at 4:38 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good afternoon,

Does the transmission up-shift okay?

This sounds like a valve body issue.

https://www.2carpros.com/articles/automatic-transmission-problems

when was the last time you changed the fluid and filter?

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

Is the check engine light on?

Roy

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May 21, 2020 at 5:09 AM
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RJRT
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Yes, it shift up fine. it’s just 0 to 20 that it has trouble.
May 21, 2020 at 5:25 AM
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RJRT
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  • 7 POSTS
I am not sure about when the filter was changed, but it had new fluid a couple months ago.
May 21, 2020 at 5:29 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Do you mean from 20 to 0?

Did you change the fluid and filter?

Roy
May 21, 2020 at 5:30 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
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I would still drop the pan and change the fluid and filter.

Roy
May 21, 2020 at 5:32 AM
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RJRT
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Yes, I meant 20 to 0.
May 21, 2020 at 8:40 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
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Okay, I would start with changing the fluid and the filter. Look for any debris in the pan or on the magnet on the bottom of the pan.

If that does not work, most likely the valve body will have to come down and gone through.

Roy
May 21, 2020 at 8:42 AM
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RJRT
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Okay, thank you. I will start with that.
May 21, 2020 at 9:01 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
You are welcome.

Always glad to help.

Roy
May 21, 2020 at 9:06 AM
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