Leaking transmission fluid is probably one of the easiest ways to identify that your transmission needs attention. Automatic transmission fluid is vital to your car's shifting capabilities, so a little fluid on your driveway can quickly turn into a major problem. Automatic transmission fluid is bright red, clear and a little sweet-smelling when everything's working correctly [source: AAMCO]. When you check your automatic transmission fluid, make sure it's not a dark color and that it doesn't have a burnt smell. If it is, you'll need to take it to a mechanic and have it replaced. Unlike your car's motor oil, the transmission doesn't really consume or burn up any fluid during use, so if you notice you're running low on fluid, then it's definitely leaking out somewhere.
If you have a manual transmission, checking the fluid levels may not be as easy as simply lifting the hood and reading a dipstick. Manual transmission fluid has to be checked right at the transmission case -- usually through the fill plug. Again, if you suspect your transmission is losing fluid, have a mechanic locate the leak and have it fixed.
If your fluid level is good, there's another easy way to know if there's something wrong with the transmission: go on to the next page to see how you can find out if your transmission is having problems -- without even having to pop the hood.