Transmission replacement can damage your budget.
Car trouble can cost you dearly, especially if you ignore problems or put off repairs. Your car’s transmission transfers power from the engine to the wheels. When it fails, you might face thousands of dollars in repair costs, an expense you could have avoided by identifying and responding to problems quickly.
1. Check Engine Light
A lit check engine light can suggest any number of problems, including a loose gas gap. It can also serve as the first signal from your car’s computer that something is wrong with the transmission. Use your onboard diagnostics tool to determine the problem. If you do not have this tool, then take your car to your mechanic for an evaluation.
See: Forbes: What That Dreaded Check Engine Repair Will Cost You
2. Slippage and Shifting
Your car’s transmission should shift effortlessly, moving from gear to gear smoothly. Transmission problems are apparent when you first place your car in drive or in reverse and hesitation is present. A low fluid level might be the cause or the transmission belt may need adjustment or replacement.
3. Lack of Engagement
You turn your ignition, the engine roars to life, and you begin to shift your car into gear. That shifting may require great effort or it may not happen at all. For a manual transmission, a clutch may have worn out. For an automatic transmission, the problem may be as simple as not having enough fluid or it could point to a much more serious matter. Check the transmission fluid first, replenish or replace as needed, then try engaging your transmission again. If the problem persists, see a mechanic.
4. Clunking, Whining, and Chattering
Odd noises that seem to be coming from your transmission such as clunking, whining and chattering point to potentially serious problems. Such noises may or may not occur in conjunction with slippage and shifting problems, and could point to other problems such as with your differential or CV joints. Have your mechanic identify the source of the problem and fix it immediately.
See: CarsDirect.com: 4 Most Common Transmission Problems
5. Burning Odor
Your transmission fluid should be clear and smell clean with virtually no odor detected. Traditionally, transmission fluids were always red or pink, but today’s car manufacturers may use fluids that are green, blue or yellow. An important trouble indicator is a burning odor, one sign that your transmission may be overheating. Usually, dirty or insufficient fluid is the reason for the burning smell, a problem often resolved by changing the transmission fluid.
6. Rock and Roll
Transmission problems may become apparent when operating your vehicle at highway speeds. Rocking, rolling and shaking may occur suddenly, indicating pending transmission failure. It might also point to other problems such as with the engine or suspension system. Take your car to a mechanic for an accurate diagnosis.
7. Fluid Leak
At any time you notice fluid dripping from underneath your car, you should examine where it is coming from. Quite often, it is water from your air conditioner’s condenser, thus the liquid will be clear. In cases where the liquid has a color, you need to rule out engine oil, power steering, and then brake fluid first. This is easier to do if the fluid on the ground matches the color of your transmission fluid, enabling you to correctly identify the problem.
See: CarTalk: Service Your Car
Reference Your Owner’s Manual
Check your car’s service manual for prescribed transmission maintenance intervals. Just as motor oil greases your engine, transmission fluid lubricates your transmission. Change both the fluid and the filter when servicing your transmission.
See Also — My Car Maintenance Schedule: Normal or Severe?
Photo attribution — “Automatic Transmission” by Vestman is licensed under CC BY 2.0
1. A problematic vehicle history. What do you know about the vehicle’s history? Have you obtained a vehicle history report, such as one from CARFAX? (Disclaimer: this correspondent is a former contributor to CARFAX). A CARFAX or similar comprehensive report should spell out the owner’s name, the service work reported, accident information and other details. Certainly, such a report will not tell you everything about the car, but a report that lists a glaring problem such as being hit on the side in an accident is a car that should be avoided. In other words, you may be dealing with a car with a bent frame. (Here is an excellent article that details the limits and sometimes the pitfalls with vehicle history reports — 
4. Most performance models. The more power a vehicle has under the hood, the more likely the owner pushed the car to its limits. Although there is absolutely nothing wrong with a performance model per se, such vehicles are typically prone to wearing out faster. For example, suspension parts may take a beating, the engine and transmission may have shorter lifespans, and other parts related to vehicle performance may wear out faster.
7. The current owner is a smoker. You might be a smoker yourself or have nothing against people who smoke. But, if you are in the market for a car, smoke is one odor you may find impossible to remove from a vehicle. Moreover, ashes may burn holes in the seats or in the carpeting. Furthermore, smoke will permeate the fabric, settle inside the dashboard and simply pollute the cabin.
