A bad automatic transmission normally presents a series of signs and symptoms that can be easily identified with careful attention. What follows is a brief description of some of the most common signs of a bad automatic transmission.
An automatic transmission that slips in and out of gear while driving is a classic sign of a bad transmission. An automatic transmission has a series of gears(normally between 4 and 5) designed for various engine speeds and loads. An automatic transmission that slips between gears affects vehicle performance and is a sign of impending transmission failure.
A bad or faulty automatic transmission will often spin without providing any forward vehicle movement. This normally happens when an automatic transmission clutch fails to properly engage the transmission gears with the engine crankshaft, resulting in a spinning or freewheeling condition.
Transmission lag is defined as a delay in transmission action or engagement. When a vehicle is accelerated, a transmission that lags will fail to engage for a few seconds before "kicking" into gear. Transmission lag normally happens during acceleration from a complete stop.
Burnt Transmission Fluid
Normal transmission fluid is pinkish in colour and almost transparent. A bad automatic transmission will often burn and/or char automatic transmission fluid and turn the fluid almost black; many times there will actually be a burnt, smoky smell to the fluid as well.
Severe Transmission Fluid Leaks
An automatic transmission that leaks a large amount of transmission fluid, whether during normal vehicle operation or when a vehicle is parked, is a sign of a bad automatic transmission.