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b.carreon
New User
Mar 9, 2012, 3:44 AM
Post #1 of 8
(2228 views)
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Automatic Transmission
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I have a 99 Ford Expedition 4.6 V8 2 wheel drive model with an automatic transmission that has about 155,000 miles on it that has gradually stopped shifting into the 4th high gear. I have changed transmission fluid and filter with no change of the shifting issue. What would be some of the probable causes of this malfunction?
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nickwarner
Veteran
/ Moderator
Mar 9, 2012, 3:06 PM
Post #2 of 8
(2163 views)
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Re: Automatic Transmission
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Does this change if you hit the overdrive on/off button at the end of your shifter?
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b.carreon
New User
Mar 9, 2012, 11:06 PM
Post #3 of 8
(2156 views)
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Re: Automatic Transmission
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No, it does not shift when the overdrive is off. It stays in 3rd gear. Before the problem started the light at the end of the shifter started to flash randomly, but would eventually turn off after about 15-30 minutes of driving. I read in my Haynes Manual that this is caused by a sensor, but don't know where it is located on my vehicle
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Discretesignals
Ultimate Carjunky
/ Moderator
Mar 10, 2012, 2:58 AM
Post #4 of 8
(2147 views)
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Re: Automatic Transmission
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The overdrive light flashing means the PCM has found a problem with the transmission system. You need to have the PCM scanned to see what code(s) it is storing.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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b.carreon
New User
Mar 10, 2012, 3:14 AM
Post #5 of 8
(2143 views)
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Re: Automatic Transmission
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I have had the Expedition scanned by an electrical mechanic who then had all the codes cleared to see which codes would re appear. After going back to the mechanic none of the same codes regarding the transmission had re appeared from the new scan. Now the overdrive light has stopped flashing and the truck still won't shift into 4th gear. Could it be the PCM sensor or maybe a solenoid switch ?
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Discretesignals
Ultimate Carjunky
/ Moderator
Mar 10, 2012, 9:08 AM
Post #6 of 8
(2131 views)
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Re: Automatic Transmission
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What were the code numbers that your mechanic had erased?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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b.carreon
New User
Mar 11, 2012, 11:57 PM
Post #7 of 8
(2101 views)
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Re: Automatic Transmission
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I don't recall the error codes that came back from the second scan, but I do remember that the mechanic told me that they had nothing to do with the transmission shifting issue that I have been experiencing. I would just like to know what my possible options are in diagnosing this and correcting this issue.
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nickwarner
Veteran
/ Moderator
Mar 12, 2012, 3:47 AM
Post #8 of 8
(2097 views)
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Re: Automatic Transmission
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He obviously wasn't able to fix it, and if he was using a generic scan tool he wouldn't have been able to access the transmission info. You need it scanned with a professional scanner and the code numbers posted up here for us to give any educated info here. If its electrical, which it sounds, the PCM is logging codes related to it. We need the codes.
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