03 Navigator has about 110k on it. I just bought it and it had small leaks from where the trans cooler and the aux cooler met. I didnt drive it like that but who know how long it had been driveing that way. I repaired that small problem. Drove it around for a few days felt good and strong. Hit 60 and the Over drive light started flashing. hit the O/D button on the counsel rpms kicked up a little bit, hit the button again they wen down. (seems to be the OD is working properly).

Next day cruising 60 the check engine and od light turn on. I got the P1744 code (torque conv. clutch sys per.) Checked the fluid looks good.
Just got done reading tons of 4R100 reveiws. The spectruim seems vast, is it worth flushing and putting in the filter and new valve body or am i sol on the easy fix?

 

Sounds like the vehicle is not going into lock up, lock up is the engagement of the clutch inside the converter. This code is set when the computer sent the command for lock up and didn't get the result it was looking for. In most cases is caused by a faulty converter or pump issues.

Since you just bought it I would guess that the previous owner got rid of it for this problem.

 

There was other reasons they got rid of it (had minor body issues) I fixed that now on this. But you can be right. Anyway to test the tcc solinoid. or trouble shoot the problem. It feels smooth going hwy speeds? Rpms staying near 2k at 60mph