Flashing "O/D Off" Light
 

My son is off to school and called to say that our 97 Explorer Limited was acting up (occassionally made a ratcheting sound and occassionally would not go into reverse). I went and got the Explorer and driving home I heard the ratcheting sound (sounded like it came from the transmission--lasted for about 15 seconds and I only heard it one time) and after it got warmed up, the O/D Off light came on and it would not go into high gear. The engine hit about 4K RPM at 50 mph but I got it home. I checked the O/D switch on the lever and it is ok. I am going to check the voltage on the lever to make sure there isn't a broken wire but I suspect it is ok since I can restart the truck and go about 300 yards until the O/D off light starts flashing. Anyway, I suspect bigger problems -- anyone out there experienced this?

By the way, in about 4 short test drives, I have not had a problem going in reverse.

Any help would be appreciated.
Jonboy

I had the flashing OD light in my excursion and it meant the tranny was toast. My symptoms were the truck would rev very high before shifting. After a few miles it would not shift automatically at all. Aamco did the rebuild in July 2005 and it has been fine since.

Had Same "O/D Off" Light
 

I had the same symptoms (O/D light flashing, plus "service engine" light, plus inability to shift into overdrive" on my 2002 Explorer. Only 61K original miles, and I have cared for it religiously.

Dealer said the same thing, "trannie is toast", and they are having to replace it with a new one. Very surprising to me after such a relatively small amount of miles put on the truck. My 3rd Ford, first time this has happened.

Fred

The O/D light flashing usually indicates that the vehicle has detected an issue with the transmission and has put it in limp home mode. It will shift it harder than usual in this mode (I have been told) and is very rough on it... the idea is to get you home/the shop so that it can be looked at.

You likely will be replacing/rebuilding that transmission shortly.

The O/D light flashing is the same as a Check Engine light coming on only it means the computer is throwing a code related to the transmission.
Have the code scanned and go from there as you may not need a whole new tranny.

Flashing O/D Light
 

I did what MDisco suggested and got the codes read, however there was not a code being sent. I had this done at a transmission shop so I went for a ride with the owner. He too suspected a code but we never got one.

On our ride, he said that the transmission was working fine but it appeared that the truck was in Low 4-wheel drive (even though the switch was set to auto and the 4x4 light was off. He thinks that it is an electrical or computer problem though no codes were set.

Does this sound familiar to anyone?

Thanks,
Jonboy88

uhh i highly doubt there is anything wrong with your 4x4 modes.... it SERIOUSLY sounds like the transmission.... at any rate i wouldnt drive it anymore until you take it to a reputable shop and have it looked at. and dont go to cottman. what state do u live in? and i dont think you'll have any codes unless your check engine light is on or has been on. transmission problems are also detectable by CEL

I live in Alabama. What is CEL?

I live in Arizona what is SES? just kidding. SES and CEL mean the same. service engine soon, and check engine light. SES is "newer" and the "check engine" light is older.... im talking fords not anything else.

Just answering your questions. Is it possible that a different reader will spit out a code? Everyone I have talked to (including the Stealer) says that the flashing O/D should be accompanied with a code. One guy says that if there is no code, then one should suspect the PCM, which also sends the signals to the 4WD unit.
Nevertheless, doesn't sound like you buy the 4WD thing. The tranny is hitting all five gears. The shop I took it to is probably the best in town and the owner says he is 100% sure that the tranny is good -- I suspect he would not say that since he watched businesss walk away. When 4WD Low is selected, there is no difference in the way the truck acts -- it goes through the gears but the engine is reving at about 4500 rpm at 50 mph...

JW

Additional note: I disconnected the battery and inspected the PCM connectors and wires -- they all looked real good. Reconnected the battery and got the same flashing O/D Off Light.

Finally got the code. I went to a Ford dealer and had a scan done -- the code set was 1729 -- probable cause a transmission switch, electronic shift control module, or pcm. Since the 4x4 controls seem to work and all of the other functions work well, the most likely culprit (I think!) is the electronic shift control module.
So I was going to take a look at it and it is not where I thought it was (drivers rear quarterpanel). Anyone know where this module is in a 97 Explorer 4x4 (Limited)? The Haynes book refers you to the GEM. The dealer reference for the part is F77Z-14B205-BD. Any help would be appreciated and if someone thinks I am heading down the wrong path, please tell. Again, everyone that has looked at it thinks it is not a transmission problem and thinks it is an electrical problem in the AWD...
Jonboy

whenever you have the problem of not being able to go into reverse, its 90% the transmission, and i further believe that because you said at 50mph you were going 4k rpms..... thats another 90% transmission problem, or tranny related part. (remember, im talking fords here) but of course i havent driven it and havent experienced the problems on my own so i cant say for sure. as for your questions, you're delving into stuff i just usually take it to the dealer for, so i can be of no more help.... but good luck tho.

This is a typical T/C problem, the ratcheting was the T/C trying to lock in 4x4 Low, the 4500rpm confirm that.

You need to remove the shift control motor and service it (in the back of the T/C),

There are threads that give directions

While it is off, manualy turn the shifter to Hi (in the back of the T/C), you will be able to drive the truck with the motor off.