I have been doing alot of research on my problem. First thing that would happen is the OD light on the shifter would start to blink. Then it seems that there is no power although the rpm's go up and the eng seems fine but the trans seems like it moves real slow and misses. Then the check eng light comes on and reads the error code of p0720. Ok have replaced the sensor that the error code tells me to replace but now it happend again. As stated before I have done some research on the blinking OD light and it seems that when that has happen most of the people that this has happen to had to replace the transmission. Can any of the ford experts tell me what is going on with the blinking OD light? It says in the owners bood to contact ford right away. I have a 32 ft bounder that has 13,000 miles but it's out of warranty. I would really hate to have to spend the money to replace the trans, Any input would be great. Thanks
Marty

 

Have you taken the plastic off the steering column and checked the wires coming out of the gearshift lever? They are known to short out, and can cause issues like you are having.

 

The code does NOT tell you to replace the sensor. It tells you there is something wrong with the input from that sensor. It's your job to find out why. Usually it is a wiring problem to the sensor, not the sensor itself. Somewhere between the sensor and the PCM there is something wrong with the wiring harness. It could be corrosion, a pinched wire, the insulation could be worn off, etc.

 

Don't know about the '99SD, but I had mucho problems with my now-gone '97 250 HD. A lot of the same symptoms, replacing the sensor didn't work (cheap to try it tho). My tranny guys swore there was nothing wrong with the tranny, but something was munging the VSS signal between the sensor and the tranny - I guess it goes through a couple other boxes before getting to the tranny. Was worse in warm weather. I'm 95% sure it was a bad connection somewhere, but I never was able to find it and fix it. It's someone else's problem now...

 

beerstalker you may have a good point as it seems that it has only happend when I would shift the gear into drive from park.
Is there anywhere that I can get a Schematic of the wiring?

Also thanks everyone for your input.

 

You don't need a schematic. If this is the problem it is usually pretty evident as soon as you pull the plastic off. The wires coming out of the gearshift lever usually rub on something right where they come out of the gearshift and short out.

If you do a search there are a few good threads with part numbers and instructions on how to replace it yourself. I think the part is less than $100 and it takes about an hour. But if you go to a dealer I think it ends up running around $300.

 

Beerstalker

you talk about the part? are you talking about a wire harness? If so what part is it called? Thanks

 

I believe you replace the whole gearshift lever, with the wiring harness and button in it.

Like I said if you can find the threads talking about replacing the gearshift lever it should explain everything.

 

Hi guys i am a rookie to the thread but here goes. 2002 F-250 4x4 7.3 diesel about 8months ago my drive shaftcame apart from the rear end took it to a heavy duty shop and they remade the shaft. Sometime later i started having vss code and oss code 720 changed the sensor in the rear end and on top of the transmission then the speedometer started bouncing around after all this the transmission forward gears quit . I replaced the transmission. Lo and behold same problem so i took it to the dealership they charged me for a recall item the camshaftsensor and told me the speedometor cluster was bad and needed to be replaced i refused the 700.00 portion for that, I bought a used one still same problem still getting the same codes for vss and oss sensor any ideas would be greatly apperciated tired of getting screwed and cant trust the dealership thanks.

 

The codes don't necessarily mean the sensors are bad. It could just as easily be the wiring to the sensors that are setting the codes.

 

I have a 2000 f250 sd 4x4 and it is throwing the P0720 code. The dealer ship cant find me a part number for the Output shaft speed sensor. also is it the same as the vss. Ive been told its on the transfer case and been told its on the back of the transmission. Need help

 

It is not the same sensor as the VSS. It is on back the transmission, not the transfer case.
The base number is 7M101, but there are different sensors with different lengths.

 

Thanks Mark. My truck is running fine so im kinda not sure where to go from here. Should I try to follow the wiring or replace the sensor. And what kind of things could be causing this. Also I have a BD torque locker in there.

 

Following the wiring is usually a waste of time. Electrically checking the circuits is the way to do it. I'd do that before blindly throwing a sensor in there.

 

Hi Marty... I am having the exact same issue you describe. Did you find a solution?... would be highly curious and very greatful!...vehicle hits the shop Monday (tomorrow) .... hoping it can be fixed with sensors.