Just spoke to Ford Dealer, they say the part number is F81Z7M101AA and it costs $55! is the part number correct?
Edit: called another dealer and he says $45.95

 

Hello team,
Thanks for your time on this. I think the issue is now fixed after replacing the sensor. I'm now posting info for other guys that run into this situation. From reading on Internet, it appears people run this issue often( often being subjective!).

Problem: P0720 : Output Speed Sensor Insufficient Input

Symptom: OD flashing when stopped and accelerator jumping RPM, again when parked( NOT *while Moving).

Difficulty level: Easy, assuming sensor going bad and not the wiring itself. If wiring issue...well, good luck.

Time: 20 minutes or less.

My Truck: 7.3 Diesel, Year 2000, Auto trans.

Part number: F81Z-7M101-AA ( Note: Depending on year-model even dealership with VIN# cannot figure out, there is another variant of the same sensor F81Z-7M101-BA). The BA is shorter and AA is longer, My truck takes AA. I got BA just in case it turned out be...


Cost: $50 with Tax for F81Z-7M101-AA

Dealer quote for replacement: $180 + tax ( I said no thank you! )

Parts needed to replace: A small ratchet and 10 mm socket.




Procedure: Remember, the sensor it located right on top of the Trans at the very end just before the transfer case. The space is limited, so jack up if you have to. You do NOT need to bring down the trans though .
Simply feel the bolt with your hand( you cannot see it- use mirror if you want to) put in your socket and loosen it( from Driver side). Once loose, hug the trans and disconnect the wiring harness from the sensor( wiring will face driver side). You really cannot put both the hand from one side (driver), the passenger side is pretty much a no-no as the exhaust shield will be happy to put some scratches and cut on you( Also, I have 5 inch exhaust).

Hope this helps:




Hope this helps, you saved over $150 for 20 minutes or less.
Disclaimer:
I accept no liability for the content of this KB, or for the consequences of any actions taken on the basis of the information provided. Wearing protective eye wear, face wear is always recommended. Any injury or loose of life, property as a result of following this procedure is strictly limited to operator performing the action. It is the sole responsibility of person following this procedure to exercise all precaution necessary before attempting and after the procedure as well. I cannot be held responsible for any inadvertent affects.

 

Nice job! I hope this solves your problem.

The short (19mm) 3/4" sensor is a TSS for a 4R100 with PTO trans. The longer (37mm) 1 1/2" sensor is the OSS AND can also be a TSS for Non-PTO units (same part works in both places...). The VIN won't be any help in determining which TSS you need, you will need the part number from your transmission to determine the type or just physically look for a PTO drive (or block off plate). It's located on the left side of the case ahead of the gear selector assembly.

 

Hello Greg, Why are the prices so different between AZ and CA? I mean, your sheets shows $24 but the cheapest I found here locally(SFO bay area) is $45.95 and all other dealers asking $55.95!

 

The parts file and diagram came from Ken (Wood-n-Things). I think he may have looked something up on Tousley or maybe PartsGuyEd's sites and printed it out. If I were to ask for the same parts at my local dealer they likely would be much higher than your quoted prices. My dealer doesn't like me...he only likes my wallet.

 

Would this cause the tranny to not shift into overdrive?

 

Some dealers have higher markups on parts.

 

what would happen if you put the wrong sensor in the trans, or would it even fit?

 

I think it will not work at all. The sensor has to be at certain proximity to the mechanical component it is keeping track of...

 

My 96 F250 7.3 had the overdrive off light flashing and hard shifting problem. I read forums about it and the only cure was go manual transmission. I finally saw a YouTube video about PSOM repair. Now this isn't just a 7.3 problem. Gas too. Take the psom out and send it to one of several companies that have made a business out of Fords error. I found two good ones on Google. One you can send in the whole cluster and get the lights updated. You can change the sensor on top of the rear end but was only a temporary fix for me. Though it may need changing anyway. Only buy oem. Important.