I have a 2003 ford Taurus which won't shift into overdrive. The rest of the gears change without problem. I was told that the overdrive does not usually go first on a transmission. Any ideas what this could be? No leaks. 133,000 miles. No check engine light.

your overdrive shift solenoid is stuck open or closed . need to replace it

Your transmission is toast. Smell the fluid on your ****** dipstick. It will smell really burnt.

More info, please. Won't go into gear,or won't shift up from low gear, or second gear or what? Be specific to get specific help.(:^) don-ohio

Usually the transmission needs to be rebuilt in that situation. It's a very common problem if that's the famous automatic overdrive transmsission. AOD I have had three trucks that have done that. It usually starts by shuttering when it shifts and than finally goes out. Sometimes the Lucas transmission treatment gives you a little more time, but it sounds too late for yours. From what I understand (mechanic told me) that when the overdrive goes out, it takes third gear with it. If you drive in hilly areas, that overdrive is shifting in and out all the time as you go up and down hills and wears it out. My Dad had that hapen on his F150 and he replaced his transmission with a junk yard transmission that turned out to have the same problem. I had that transmission replaced with a Jasper rebuilt and it worked great. I think it was $1300 for the rebuilt trans with the old one core trade in. I think when 3rd gear goes out, you can only go about 45mph without over reving the engine. I saw that same problem with a Ford Crown vic with that same transmission and 302 engine that my neighbor had.
Did your third gear just go out all of a sudden or were you getting like a shuttering or kind of a grinding sound when it shifted?

You can try changing the transmission fluid and filter, sometimes dirty filter/broken down and dirty fluid can cause shifting problems. (I assume you checked to see if it had enough transmission fluid?)

Solenoid pack in trans. Position module,is just that. Wrong guess. What tran model do you have? You also have other sensors to consider but have to know the trans your working on and the computer and shift stratagy involved to solve this,even if your throwing parts at it.

HAVE U RUN THE TROUBLE CODE TEST ON THE TRANSMISSION CONTROL MODULE? IF NOT THAT IS THE 1ST PLACE U START, YOU MOST LIKELY HAVE A FAILED TRANS BUT THIS CAN ALSO BE A TRANSMISSION CASE CONNECTOR PROBLEM OR THE SHIFT SOLENOIDS OR THE POWERTRAIN CONTROL MODULE, PULL THE TRANS CASE ELECTRICAL CONNECTOR OFF AND CHECK FOR WATER OR CORROSION ON THE PINS, THE TRANS IS SHIFTED ELECTRONICLLY SO DO THE TEST 1ST.

The overdrive circuit is is faulty and will have to be replaced or short in the wiring .

The ford taurus is know for having a weak transmission, however if the transmission is serviced regularly you can avoid problems.