my tranny switches from 1st to 2nd smooth but will not go into 3rd. when it switches it goes into a neutral and over revs the engine. if i cut overdrive off it will stay in 2nd gear and i cant run but 40 mph or i will damage my engine. i tried lucus transmission fix and still the same. i did some google searches that led me to believe it was a speed sensor so replaced that and still exactly same problems. any ideas would be greatly appreciated. thanks. ED

 

Could be a bad solenoid pack, shift module, or even a mechanical failure. With something like this you're always better off bringing it in to be hooked up and scanned. One wrong guess and it will cost you much more than the diagnostic fee.