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.
It could be because the bulb is burned out ot he wire is disconnected.
If "OD Off" is lit, then your overdrive is off.
its basically the same thing. an automatic tranny wont go in Overdrive until youre going at a generally constant speed. the same is true with a manual transmission- while driving on average roads (40-55 mph) you will not shift into the final gear until you are going at a constant speed. Overdrive is a gear that turns the vehicle driveshaft faster than the engine and is used to improve fuel mileage (and also lower CO2 emissions). Typically 5 or greater in a manual or 4th gear or greater in an automatic is overdrive but there are exceptions. Because of CAFE (fuel economy standards) virtually all cars and small trucks have come factory with ovedrive since 1981.
Because it does not have an overdrive gear.
Because it's old
yes it is a good solution for a damp basement because it helps prevent moisture, sweating pipes, metal objects getting rusty, and musty odors in your basement.
Only if you want to shut off the overdrive feature , because overdrive is the normally allowed position
OD means Overdrive. The light is on because you have disengaged the Overdrive. The button is on the shift lever on the side. Push that button to engage the overdrive.
Because you turn on the light
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.
Overdrive is the normally allowed position , but unless you are going fast enough it will not shift into overdrive because it acts as the " top " gear ( on my Explorer I have to be going 50 miles per hour / 80 kilometers per hour before it shifts into overdrive )
Turns the Overdrive on and off. Used for towing because you should never tow with the transmission in overdrive.