Answerthe vehicle speed sensor can cause this problem or it can be the thermostat.i had the same problem and it worked for me.
The same thing happened to my dads 96 Chevy S-10. The transmission was rusted not allowing it to shift. I would have the transmission checked out.
what would transmission not to shift in to overdrive
the overdrive sencer
My 1984 corvette transmission is not shifting into overdrive. It shifts first thru third fine.
Assume it's an automatic. You probably have a bad valve-body or clutch pack in the transmission.
It is not recommended to pull a trailer with automatic trans in overdrive, put in drive only. When attempting to pull without locking out overdrive, trans will continue to shift from drive to 0verdrive causing a massive heat buildup. Heat is not good for automatic transmissions, and will eventually cause failure, causing your wallet a very bad day!
What you're calling "overdrive" is probably torque converter "lockup". There's a good chance that it's a sticking relay inside the transmission. If that's the cause, be grateful, since a rebuilt transmission is about the only other option.
Your transmission might automatically shift out of overdrive while driving on the interstate because of low transmission fluid. This issue might also occur because of a bad transmission sensor or overdrive sensor.
That car is equipped with a 4R70W electronic automatic transmission through the 2005 model year, and the Overdrive OFF switch is on the end of the shift lever. Push it in to disable Overdrive, and again to re-enable Overdrive. This feature is typically only used when towing or in very hilly or mountainous terrain that would cause the transmission to "hunt" between Third and Fourth gear a lot.
If the transmission is healthy and any/all adjustments are done properly there should be no slippage.