A car owner can tell if the transmission is going out if there is a lack of response or leaking transmission fluid. A whining noise can also indicate a failure.
If a vehicle refuses to go into gear or if there is a delay after shifting, this can indicate that the gears within the transmission are seizing up or becoming worn down.
If transmission fluid begins to leak, it indicates that a seal or gasket within the transmission has failed. If the car is driven without transmission fluid or with severely low levels of fluid, it can cause permanent damage.
A whining or humming noise can also indicate a failing transmission. This can be caused by low fluid levels or seized gears.