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valleybusman
Top Member

USA
804 Posts
Posted - 03/13/2023 :  08:51:56 AM  Show Profile  Send valleybusman an AOL message  Reply with Quote
Have 2018 All American. Driver couldn't get his transmission to work. Looked and had P0720 code. Speed sensor. Could it be just a sensor? This is not the first time. When I looked up the code it said inactive. So, it has happened before.

tigger2
Advanced Member

USA
470 Posts
Posted - 03/13/2023 :  11:50:15 AM  Show Profile  Click to see tigger2's MSN Messenger address  Reply with Quote
Check the bolt holding the rear drive line yoke on the transmission for being loose. Yoke holds cutter wheel tight on shaft loose wheel intermittent speed signal.
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valleybusman
Top Member

USA
804 Posts
Posted - 03/14/2023 :  04:36:04 AM  Show Profile  Send valleybusman an AOL message  Reply with Quote
Tigger2 I checked the bolt and it was fine. I also looked at the speed sensor and it was tight. Anybody have any ideas what to look at next
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g0ttadrift
Advanced Member

USA
258 Posts
Posted - 03/14/2023 :  07:04:24 AM  Show Profile  Reply with Quote
I would change the speed sensor. Sometimes the resistance gets out of calibration and will set this code. Could be built up resistance in the wires as well.
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valleybusman
Top Member

USA
804 Posts
Posted - 03/14/2023 :  1:52:51 PM  Show Profile  Send valleybusman an AOL message  Reply with Quote
I went to order a speed sensor and they came up a retarder senser and a speed sensor. Which do I need and where on the transmission is it. On the back by the yoke?
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g0ttadrift
Advanced Member

USA
258 Posts
Posted - 03/15/2023 :  07:39:14 AM  Show Profile  Reply with Quote
If I remember correctly, it's a speed sensor and it's on the very top of the output tail housing of the transmission.
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Bluenozer
Top Member

Canada
644 Posts
Posted - 03/16/2023 :  07:11:07 AM  Show Profile  Reply with Quote
all three speed sensors have the same part number and same resistance if I remember
OEM trained in wiring and all engine platforms for over 20 years
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valleybusman
Top Member

USA
804 Posts
Posted - 03/21/2023 :  2:08:47 PM  Show Profile  Send valleybusman an AOL message  Reply with Quote
The sensor had a crack
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g0ttadrift
Advanced Member

USA
258 Posts
Posted - 03/22/2023 :  04:20:04 AM  Show Profile  Reply with Quote
Thanks for the follow up! Glad you found the issue.
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