Being aware of the warning signs of transmission trouble can help you out in diagnosing problems and in avoiding bigger issues down the road. Here are some issues to look out for:
1.) Automobile refuses to go into gear - This one's only a concern on manual vehicles. If your transmission refuses to budge when you try to shift, you know you've got a problem
2.) Burning odor - Any bad smell coming from your auto is bad news. If your transmission fluid gets too low you run the risk of what remains burning off, causing further damage.
3.) Transmission Noisy in Neutral - It seems intuitive that if you hear weird noises when the car should be shifting, that the transmission is acting up. But would you suspect it if things were going "bump" in neutral? Yes, it could be the transmission. Such sounds could have a simple and inexpensive solution -- as with many of the problems on our list, adding or replacing the transmission fluid sometimes does the trick. Alternatively, lots of noises from the transmission while it's in neutral could signal something more serious, like mechanical wear that will need the replacement of parts.
4.) Gear Slippage - If you experience your car spontaneously popping out of gear and back into neutral, it's definitely time to get your transmission inspected.
5.) Leaking Fluid - This is one of the most obvious issues you might experience. Automatic Transmission fluid is usually bright red and smells slightly sweet. If yours is leaking, get your car checked out, but not before topping off.
6.) The Check-Engine Light is on - The check engine light in many models can come on for all sorts of reasons, transmission issues among them. Don't overlook it. Many mechanics and auto parts shops have diagnostic tools that can help narrow down the cause.
7.) Grinding or shaking upon shifting - If your car makes a grinding sound (manual transmission) or shakes violently while shifting (automatic transmission), you might be in need of transmission repair.
8.) Whining, Clunking and Humming Sounds - It's hard to say exactly what your car will sound like if there's transmission trouble, but you'll probably know something is wrong when you hear it.
9.) Lack of Response - Transmissions are designed to go into the correct gear every time, so when they hesitate or refuse to go, it's a sure sign there's something wrong.
Originally from howstuffworks.com
Nine Signs of Transmission Trouble
