Travelin' Scott - I too am having the same problem with my 200 F250 SD 7.3. Along with the speedometer and A/C not working, the OD light continues to flash as well as my ABS light is on in addition to my blinkers not working. I have replaced the transmission in it with a new one about 5 years ago and am hoping that it IS the VSS. I am going to try to see if that does the trick and replace it. I was also told by an electrician that it might be the ECM module. He stated that there are 2 of them... I'm not sure, I have to do some more research on that part. Going to try the VSS and hopefully it'll fix my problems!
Thanks for your thread.

 

Do you go to your mechanic for wiring problems in your house? There is one module, called the PCM (Powertrain Control Module) that operates both the engine and transmission. It's not likely to be the problem, though it is possible.

If you want to spend a lot of money changing parts without knowing what's wrong is a good way to do that. If you got the codes read we'd know what the PCM sees as the problem and would be able to steer you in the right direction. The places that read codes free CANNOT read Ford transmission codes. You need either a good independent shop or a Ford dealer.

 

[QUOTE=Mark Kovalsky;18071984]Do you go to your mechanic for wiring problems in your house?

LoL .... Mark, it wasn't with an electrician for the house.... it was an electrician that specifies in vehicles! I can see where when reading it, the mistake could be made. And if my mechanic knows anything about the wiring in my house...... MORE POWER TOO HIM!!! LoL .
My son in law works for a reputable mechanic company here in town where I live and he can get the codes for me with the truck and I'll go from there. THEN I will take it to my (vehicle) electrician. When I took it there before, they told me also about the PCM and ECM modules. But like you said, lets start with the basics and know where to troubleshoot first before we go and spend dollars.

 

Now it makes a lot more sense!

 

Th overdrive button is blinking n its stuck in 2nd gear i think

 

It's blinking because trouble codes have been stored in the computer's memory. Being stuck in a gear is one thing that can set a code, but that's usually due to some other failure. The stuck in gear is a symptom of a problem, not the cause of the problem.

 

So I've read this thread and others regarding the blinking OD light. I have a '99 F350 SD w/7.3 PSD. The OD button started blinking last week out of nowhere. Searched the forums for ideas. Had my neigbor bring his scanner from his shop and run scan. Pulled codes P1670 and P0755. I took the ol truck to transmission shop for them to check and confirm my findings. They came back with the same codes and price of $850ish to replace shift solenoid pack and CPS. Question I have is since this is the code being thrown, will this fix the issue? Some say chase the wiring harness connectors and others say tranny work. From another post from Mr. Kovalsky he stated that a wiring issue would not throw the code so I'm hoping that by fixing the specific code issue, this will stop the slow shift from 2-3. The only physical driiving issue is when the OD light is blinking, it is slow to shift from 2 to 3. When OD light is not blinking the truck drives just fine. Thx.

 

It's not the wiring. Neither of those codes say that there is an electrical issue. The P0755 indicates that there is a problem with the shift solenoid. I recommend replacing the solenoid body.

I'm not familiar with the P1670 code. The description I have is Electronic Feedback Signal Not Detected. Possible causes:
Open fuse
Faulty Injector Driver Module (IDM) relay
Open or shorted Injector Driver Module (IDM) enable circuit
Open/short in EF circuit
Open/short in Fuel Delivery Command Signal (FDCS) circuit
Injector Driver Module (IDM) powering circuits
Faulty Powertrain Control Module (PCM)

Read more: https://www.autocodes.com/p1670_ford.html

 

So I replaced the Shift B Selonoid last July since that was the code being thrown. All good. Until yesterday and light started blinking again. Drove fine yesterday. Then this a.m. I did have a slight bump in shift from 1-2 and 2-3. Then when I got to work and put her park, the light stopped blinking. Gonna try to get her scanned today. Surely the selonoid should last longer than 5k miles. Will post back after I get the code.

 

UPDATE: Had the truck scanned on Thursday and the codes are as follows:

P0743 TCC System Electrical Fault
P1728 Transmission Slip Error-Converter Clutch Fault
P00741 Torque Convertor Clutch System Stuck Off

When I checked the tranny fluid it was low. So my neighbor with scanner said to add fluid. He then cleared the codes. Added fluid and checked the next day after the truck warmed up to operating temp. The level showed just in the middle of the Hot section of the dipstick. Level good. I got in and drove to the park and after approx. 10-15 mins drive-time, the OD light began blinking again. Checked level when I arrived at the park and level was now at the lower portion of the Hot section. After arriving home later I noticed there was trans fluid leaking out onto the street. Crawled under and noticed fluid on the underside of the trans pan and also was fluid dripping from a spot just in front of the pan. Don't know what it is called but looks like a small weep hole maybe. Located between the oil pan and trans pan. I checked fluid again and it was still showing in the middle of the Hot section on the dipstick. The truck has driven fine all this time Saturday. Then today Sunday morning driving to work, 10 mins into the drive the OD light begins to blink again. I get to work (20-25 min drive) and check fluid and it is showing on the lower end of the Hot section. There is no dripping as of this morning. Confused. I'm not a mechanic by any means, but guessing the codes were thrown due to low fluid (low fluid causing something to stick or not operate properly) and with fluid level in the normal operating level, wouldn't that stop the OD light from blinking? Am hoping to get truck scanned tomorrow morning and check if this round of blinking OD light is the same codes as were the ones from Thursday.

 

I've been reading the threads on here for the last hou . The problem I ran into tonight was the overdrive was blinking and the trans temp was high at 250. Drove it for 20 mins like that before I could pull over the trans temp dropped to 180ish and the blinking went away. Any ideas. Trans shiftsled into neutral it seemed like before this happened the after it got hot it wasnt as ba . Could the tune be to much? New truck to me and dont know what's on the tune..

 

My idea is it got hot. You could see if I'm right by reading the codes. A code was stored in memory when the light flashed. Get the code.

 

Mark the codes I got were
p0603
P0478
P0470
P1211
P1783
The last one said trans got ho .

 

The first thing to do is see if there is something blocking the airflow to the coolers, i.e., the radiator, the trans cooler, etc. After driving for a while see if the line from the front of the trans to the radiator is hot. If it isn't hot you either have a flow restriction in the coolers or your cooler bypass has failed. They bypass is very easy to rebuild. Summit Racing has a kit to do it for about $25.

 

My 96 f250 7.3 does the same thing. Driving normally. OD light starts blinking then hard shifting. I replaced the sensor on top of the rear end. This fixs it temporarily but eventually it keeps happening and now more frequently. Im on my 3rd sensor. Something is causing the sensor to go out. Probably a bigger problem. I also read that it may be something electrical getting to hot because the motor is to big for the truck and the wiring is to close. I still cant take the truck out of town.