the overdrive is not working

1991 FORD F-250
160,000 MILES
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TOMCRIT
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I have a 1991 Ford f250 and when i start the truck and put it in gear it will not go if i turn the overdrive off then it will go what is the problem and how do i fix it
Jul 27, 2012 at 8:01 PM
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ASEMASTER6371
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you have some sort of internal issue. have it scanned for codes and get back to us with the code. it most likley will have to be removed and rebuilt

Roy
Jul 27, 2012 at 8:07 PM
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TOMCRIT
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If i get the speed past 35 MPH and turn it back on it works untilled i have to downshift to pull a hill
Jul 27, 2012 at 9:56 PM
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TOMCRIT
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My truck doesn't. Have a slot for a code reader under the dash
Jul 27, 2012 at 9:58 PM
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ASEMASTER6371
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it is an obd1 system that is under the hood.

Roy
Jul 27, 2012 at 10:10 PM
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TOMCRIT
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OK i will have it checked i am used to having them under the dash
Jul 27, 2012 at 11:01 PM
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RACEFAN966
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The sensor on the rear end is what controls that they are about 20 dollars and easy to replace. Just did another one of those a couple of day's ago same problem.
Jul 28, 2012 at 4:00 PM
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TOMCRIT
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Last night driving home lost all gears. Had to use four wheel drive wondering if i didn't know some crud loose and cloged. Filter it acting like it is not getting any vacuum. Wants to move but wont
Jul 28, 2012 at 10:56 PM
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RACEFAN966
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There is no vacuum that operates the trans it is done electronicly with the use of the sensor on the top of the rear diff. You may have a bigger problem with the trans, if it was able to still move then I could have you run a test. How is the fluid?
Jul 29, 2012 at 4:04 PM
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TOMCRIT
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It was not burnt or anything i am going to drop the tranny pan. To see if i have any metal shavings in the oil could it be the filter is just clogged and it is not able to suck guild thou out the tranny?
Jul 29, 2012 at 8:46 PM
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RACEFAN966
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It could be plugged which would cause an insufficiant flow of fluid. Let me know what you find.
Jul 31, 2012 at 4:05 AM