A car that makes strange noises or begins to drive oddly can be dangerous and terrifying to drive, especially if you're unsure of what is causing the vehicle to behave oddly. Some sounds and actions can be attributed to a variety of car problems, but others make it easy to pinpoint the source. Either way, it helps to know what you're dealing with.

When it comes to the transmission, catching a problem early on can help you avoid further damage. This is especially useful because repairing a transmission system usually does not come cheap. There are a handful of sounds and other signs that correlate with mechanical difficulty in the transmission. 

Common sounds associated with a transmission are buzzing, clicking, humming and clunking. When the car is in neutral and still making a lot of noise, the reverse idler gear or worn bearings could be making the racket. You may also feel sensations that indicate tranny problems, such as grinding and shaking.

If your transmission has difficulty switching gears, there might not be enough transmission fluid in the system. If this is not the case, chances are that internal parts like the shift linkage are worn or wearing out. Electronic sensors or the computer on modern cars could also be malfunctioning.

Internal issues such as those listed above can also cause the tranny to slip out of gear. If this happens while driving, you may be unable to control the car, as the transmission might be disconnected from the engine.

Those who drive stick shift need to keep an ear out for a dragging clutch. Essentially, a dragging clutch fails to fully disengage from the engine and makes it difficult for the driver to shift the car into the appropriate gear. You'll notice this if you hear a loud grinding noise when you try to shift. This probably happened at least once or twice when you were learning to drive manual and getting the timing of alternating the clutch and the transmission down pat. Now that you're adept at handling a manual transmission, you'll know whether the abrasive sounds are your fault or an internal clutch issue.

The transmission fluid is a fickle beast as well. Too little fluid can lead to poor shifting and damage the transmission if it is not addressed. If you add more tranny fluid and find the levels are low again rather quickly, you might be dealing with a leak. The transmission has a few areas where leaks often crop up - the filler tube base, the drain hole below the tranny, the speed sensor mounting point, the selector shaft and the radiator. The owner's manual can help you locate these parts to inspect them for signs of leakage.

When you see the check engine light illuminated on the dashboard of your car, it could be related to the transmission. However, this indicator is also tied to a number of other parts and systems, and more often indicates a failing oxygen sensor or a missing gas cap. There are devices that can read the code so you can determine the root of the problem.

If you suspect your car's transmission is acting up or breaking down, you should address the problem as soon as possible to avoid further damage. When a transmission begins to break down, continuing to drive the car will only exacerbate the situation, which can make the vehicle unsafe to drive.