[waynetx383]

I have an '04 and I went out a few weeks ago and everything worked great. The next day I had no speedo and threw a P0720 code. I've replaced the OSS sensor, and done the gauge cluster self diag test. The old and new sensor both ohm test fine and the gauge sweeps properly. I've also checked the signal voltage and ohm readings per the ford service procedures and they all check out ok. The wire harness looks fine with no visible cuts or other damage to it. I had the trans rebuilt a couple months ago and noticed when I pulled the old OSS sensor that the magnet on the end was covered in metal shavings. Seemed a bit odd on a rebuild and makes me wonder about the quality of their work. From what I've read the OSS reads a 12 teeth gear as it rotates in the output shaft and uses that reading to calculate the speed of the vehicle. Is it possible that the gears broke, or do they serve another function as well? This is the 3650 5-speed btw. Does anyone have any other suggestions? The ford service manual says replace the PCM if everything else checks out, but it seems far fetched to me that it would only throw one code if the PCM was bad.