Check the fluid level. Check for trouble codes with a scanner, Check shift linkage/vaccum lines.
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.
you might need a new one soon. but first check your transmission fluid.
Might be a problem with the brake/transmission interlock switch
The signs of a bad transmission in a Mazda might include hard shifting or a refusal to shift into certain gears. A revving of the motor during the shift can also be a sign of a bad transmission.
Your '01 Lincoln Town car might not shift gears because it is low on transmission fluid or because the transmission is damaged.
too low trans flid
A 2007 Chrysler Sebring that will not shift out of Park will probably need a shift solenoid replaced. This is inside the transmission and the transmission might have to be taken out of the vehicle to be fixed.
One of the reasons a transmission might not shift into overdrive could be a problem with the belt drive inside the transmission. Belt drives can be stretched over time. Another reason could be that the transmission fluid is low or very old or the filter is clogged.
there is no fuse that makes the transmission shift the transmission shifts on cylinoids and rpms
A transmission that is not engaging fully when in drive might need a new shift solenoid. There is also a chance that a band is stretched or broken inside the transmission.
If your 1997 Chevy diesel will not shift into overdrive, you might have an issue with a transmission sensor. Some of these vehicles have several sensors that must engage in order to shift.
check your transmission control relay.. it might be stuck..