Transmission not shifting properly

2004 FORD EXPEDITION
100,000 MILES • 5.4L • V8 • 2WD • AUTOMATIC
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STEVE MCDONALD
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I replaced transmission in vehicle listed above and it wouldn't shift. the mechanic said I needed to have computer reset and someone said it maybe transmission and try reset. Now, I talked to mechanic at Mr. Transmission he said that I don't have to flash it. that I don't have the kind of transmission that need it. so would do you think? I need to flash it to see if it shifts because I don't want to waste $90.00. And do you think I can drain it and try the Lucas first?
Jul 6, 2018 at 2:03 PM
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KASEKENNY
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If all you replaced was the transmission then they are correct that you do not need to program anything for this unit.

Did you replace the transmission for this issue and it did not change it or did you have this issue only on this transmission? In other words, why did you replace the unit? Also, where did you get this transmission from? Was it a new unit or did you get it out of another vehicle?

We need to check the fluid and just make sure it is correct. I attached the process.

Let's start with this and go from there.
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Nov 12, 2020 at 9:26 AM
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STEVE MCDONALD
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The transmission shifts hard and jerks when shifting from park to reverse. It is a replacement transmission. What is the problem and the fix?
Nov 12, 2020 at 2:31 PM (Merged)
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ASEMASTER6371
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Good afternoon.

The first thing I would check is if there are any codes.

Was this a new or used transmission?

I would drop the pan and check the filter for any debris. Dirt may be in the valve body causing the valves to stick giving you this issue.

One other thing. Make sure the engine idle is not too high. A high idle will cause a rough engagement of gears.


Roy

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

https://www.2carpros.com/articles/automatic-transmission-problems
Nov 12, 2020 at 2:31 PM (Merged)