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 ( in overdrive the engine doesn't rev as high , the gas mileage is better , the transmission will run cooler etc. when you drive at higher speeds )
highway driving
According to the 1995 Tracer's Owner Guide (page 241): Overdrive is the usual driving position for an automatic overdrive transaxle(transmission). It works the same way D (Drive) works, AUTOMATICALLY upshifting or downshifting as the vehicle speeds or slows. However, Overdrive also shifts into a fourth gear (an overdrive gear) when your vehicle cruises at a consistent speed for any length of time (like on the Interstate). Overdrive will increase your fuel economy when you are traveling at cruise speeds (usually 50mph or higher). But, Overdrive may not be appropriate for certain terrain such as hilly or mountainous roads because the transaxle (transmission) automatically shifts back and forth between 3rd and 4th gears while doing this type of driving. Therefore, it is recommended if your car is continously climbing hills/mountains (which requires additional power) then you should shift to D (Drive).
Your transmission is shot. Have a new one installed with a warranty. Just a side note: if you live in hilly or moutainous area, lock it out of overdrive for local driving. Reserve overdrive for interstate highways. When the transmission has to constantly shift up and down it will wear it out prematurely.
Transmission Problems, you shouldn't be driving with this on!
Overdrive ON is the normal position But if you are towing something or driving in hilly country where the transmission is constantly shifting from overdrive to drive , then you want to switch the overdrive off
It's not recommended to use overdrive on a constant base. It stresses too much the engine as well as transmission.
The overdrive warning light might start flickering when you are driving because of low transmission fluid. This light could also come on because of tension on the transmission while you are towing a boat or trailer.
More than likely the transmission has gone into overdrive.
why does the 1991 Lincoln towncars transmission not have overdrive?Instead of going into overdrive it seems to go into neutral.But if you take it out of overdrive and leave it in drive it never goes into neutral while I'm driving.
Generally speaking, overdrive (O/D) is the highest gear in the transmission. On most cars the automatic transmission has 3 speeds and Overdrive (forth speed). Overdrive allows the engine to have less rpm with higher speed in order to have better fuel efficiency. When you switch it on, you allow the transmission to shift into overdrive mode after the certain speed is reached (usually 30 - 40 mph depending on the load). When it's off, you limit transmission shifting by third speed.In normal driving condition the overdrive should be always on.You may need to switch it off when driving in mountainous area or towing a trailer.[The automatic transmission automatically shifts from OD to the 3-th gear when it feel more load. When it feels less load it shifts back to the O/D, but under certain conditions, e.g: driving uphill or towing a trailer, the transmission can not decide to stay in OD or to shift into 3-th speed and it starts to shift back and forth. That's the time you may switch it off and help the transmission to decide.] .You also may need to switch it off when you want to slowdown using the engine braking, for example, driving downhill. [For more details, check your owner's manual]
Overdrive in Subarus, like just about every car with an automatic transmission built in recent memory, is built into the routine working of the transmission. Your transmission selector, if it's like mine, has a "D" for drive then the next digit down is a "3". Choosing the "D" allows the vehicle to access overdrive when appropriate. Driving with "3" as your chioce does not allow the overdrive to work. --Ken