First my question; is it imperative that my transmission gets rebuilt ASAP, or is it really ok and safe to continue to drive with just a tranny fluid flush/filter change?

Now for the details;

I put my 95 Explorer Limited up for sale last week. It has almost 138K miles on it, I got the oil changed and the same evening I was driving home from work and "OD Off" starts flashing. So I take to a local shop and he directs me around the corner to Aamco. The guy at Aamco calls me later and says he found code 647 (incorrect gear ratio after third gear was commanded) in there but can't tell what lead up to that because the history had been cleared. I recently replaced the battery, so it gels. He says they do not believe there is any major damage yet, no big chunks of metal sitting in the pan or anything like that. He suggests getting it rebuilt and after researching, the price he is asking would be fine for me if I did not already have it up for sale. The code has not come back since I got it back from the shop, but I've been avoiding driving it in case. Today I took it out for a good spin and all seems ok. What suggestions can you offer?

 

I believe the light starts flashing when the computer doesn't find that proper relationship for the input and output shafts given a specified gear ratio - in other words the tranny is slipping.

You may be lucky and it needs service and adjustment. However if you ignore it then it will be likely that it will need to be overhauled.

Just my .02 on the issue.

 

Well my major predicament is that this fault showed up after I put it up for sale and had a fairly serious buyer asking about it. A week after it was checked out the OD Off light is flashing again. I am not a mechanic and don't know what to look for. What I have noticed;

When I back it out and then drop it into drive, it seems to take a moment to actualy get into gear so I can pull out.

The shifter is a bit off, it s not centered on the gear and when you put it in park, the vehicle is not settled until you let go of the shifter and brakes an it sort-of settles into park.

Please let me know if this means anything or if there is anything else to look for.

 

I'd take it to Ford and have them to a diagnostic on the tranny. I don't know what TSBs may be out there for your box, nor do I have any real good ideas on how to proceed. If there is an issue with the tranny you may get a better service job at the dealer than anywhere else - IMHO