Have an 03 Crown Vic P71 with167,000 miles.... trany works fine, just keeps getting confused which gear it should be in 3rd or 4th when going between 40 and 55 m.p.h. with OD on or off. Three mechanics including Ford dealer scanned it and found no error codes but all said I should replace trany at between 2000 to over 4000 dollars reguardless. Decided I had nothing to loose but vast amounts of money and more hair and did a Hail Marry and bought some Lucas Trans Fix. After removing a quart of trany fluid I put in the Lucas and the results were immediate....it was now much worse so I opted not to panic and give it some more time and miles to do its thing. 300 miles later and another 1/2 bottle added something happened, the problems vanished after driving only a few minutes (warm up time) the transmission is performing as it should...or it may have heard me when I said this better fix it or down the road you go....funny how that happens isn't it?