Was passing a slower driver on the way home from work. Tranny has not shifted into overdrive since. Shifting from 3 to D there is no change in rpm`*. 70 mph is approx. 3000 rpm`*. My mechanic says there are no codes. He pulled the pan and said the tranny was very clean inside. 104,000 miles. I got a new valve body but still have no overdrive. Tranny shifts fine thru all other gears. I have not noticed any kind of slipping or eratic shifting. There is some sort of humming noise when the gear selector is in D at 50 mph or higher, but the noise goes away when the selector is put into 3. Noise is not very loud. A service light never came on to let me know there was a problem. I just noticed the rpm`*. Any suggestions would be helpful as there are no codes to point me in the right direction.

Shifting from D to 3 while going 50 cant be too good to begin with. I think overdrive only occurs when the selector is put into overdrive to begin with, the (D) instead of D, and regular drive wont go into overdrive (pretty sure)

The selector can be put in (D) if you prefer and it will not shift into overdrive. The point being when the shifter is in (D) and it is put into 3 there is no change whatsoever. No change in rpm`* or no gear change. The normal gear change ( at least in my car ) is approx 45 mph. I have never tried to see exactly so I may be a little off. I was thinking ( after reading other posts ) that possibly I have a solenoid problem of some sort. I have read several posts about aTCC problem.

Ahh, got ya now. Your tranny should do something at least, I would imagine switching gears like that.

Where at in TN are you from? I lived in Clarksville for two years