It sounds like a pressure actuated servo might be on the verge of failing.
Electro-mechanical items are hard to diagnose as they fail partially and can fail from an electrical reason, circuit sends incorrect voltage from bad sensor or speed sensor sends incorrect voltage to computer and this causes a problem.
The issue sounds dependent on temperature, so it is most likely a transmission solenoid. When it is cold the transmission fluid may have higher pressure due to the cold temperature and the transmission on your car is all aluminum and does not hold heat so the fluid stays thicker and pressures are higher. This could be causing the difference in performance as the transmission depends on, "pressure signals" to send electrical signals to the cars computer to determine what gear the transmission should be in. The temperature can even affect electrical circuits, but that is not as likely.
Either way, the transmission certainly needs to be serviced by a certified repair shop, this site can help you find dependable repair shops near you.
Start noting if the performance on cold days changes the longer you drive it, (and thus hotter the tranny fluid gets), and if shifting it manually with the shifter seems to override the issue.
Things like this will help the technician diagnose your vehicle more quickly and save you some money as intermittent failure parts are tough to diagnose.
I hope this information helps you.
Saturday, February 19th, 2011 AT 10:09 AM