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Transmissions

The point of a transmission is to get the power from the engine to the wheels of our vehicle and to allow us to move at a wide range of speeds. A transmission, whether automatic or manual, essentially changes the size of gears that turn the wheels of our vehicle slower or faster while preventing undue stress on the rest of our vehicle.

With a standard, or manual, transmission, the driver presses the clutch which essentially disengages the gears and allows movement of the shifter into the desired gear. The driver releases the clutch and the selected gear engages. When the driver wants the vehicle to move faster or slower, the clutch is engaged and the new gear chosen and clutch released. An automatic transmission does the same thing but without much driver intervention. The driver selects direction drive or reverse (there are a couple extra “special” gears). The transmission automatically selects the most efficient gear and carries out the process of shifting automatically.

WHAT CAN I DO TO PREVENT COSTLY AUTOMATIC TRANSMISSION REPAIRS?

The best thing you can do to protect your transmission is to have it checked regularly. You can monitor the automatic transmission fluid yourself by inspecting for leaks, making sure the fluid is at the proper level and is not burnt or dark in color. Additionally, verify that the fluid has a viscous quality. The viscosity of the fluid is what protects the transmission. Check your owner’s manual and service the automatic transmission according to their recommendations; but, do it more frequently any time the fluid begins to break down or become dirty. When you change your fluid also have the filter replaced at the same time.

Heat is the biggest cause of automatic transmission fluid breakdown. Towing, hot weather, stop-and-go traffic, and mountain driving all contribute to causing more heat that can break down automatic transmission fluid. If you engage in any of these activities you might consider installing a transmission cooler. It’s kind of like an extra radiator to keep your automatic transmission fluid cooler.

You should never shift from park if your engine is racing. You should not shift from one direction to another until the car has come to a complete stop.

HOW TO CHECK YOUR AUTOMATIC TRANSMISSION FLUID

The best thing to do is check your owner’s manual first. Generally speaking, the transmission dipstick will look similar to the oil dipstick, but bigger. It may be marked (TRANS or ATF or it may be colored red). The oil dipstick is usually near the front and the automatic transmission dipstick is usually towards the back and to one side. Checking the level of your automatic transmission fluid is done differently than checking your oil.

On older model cars, the automatic transmission fluid must be checked when the car is warm (has been run for a while, 10-15 minutes), newer cars may have different areas marked on the dipstick for the proper level when the car is hot or cold.

Put the gear shift through the gears (forward, reverse, etc.) to make sure the fluid is distributed properly. Park your car on flat and level surface and engage the emergency break. With the car running, pull out the transmission dipstick and wipe it off with a clean lint free cloth. Reinsert the dipstick all the way down into its tube and remove again. There should be some fluid on the stick (it may be red, pink, or gold) along with lines to tell you if the level of your fluid. If there is no liquid on the dipstick try again making sure you insert it all the way. If you still have no fluid showing on the dipstick you probably have a serious problem. It’s probably best to turn the car off and have it towed to a reputable mechanic that does transmission work. At the very least, put more of the proper transmission fluid in the car (see below).

If the liquid is dark brown or black and/or smells burnt you need to have it checked out and probably replaced. If you don’t service it promptly, you could be looking at some serious expense in repairs.

You MUST have the proper automatic transmission fluid for your car, check your owner’s manual. You add automatic transmission fluid to the car while it is running right into the tube you took the dipstick out of. Use caution and do not overfill as this can cause serious problems.

WHAT DOES TRANSMISSION FLUID LOOK LIKE

Your transmission fluid should be a transparent, viscous, and depending on the fluid, red, pink, or gold in color. If it smells burnt and/or is dark brown or black you need to replace your fluid and filter. It would be best to have it checked by a professional.

LEAK-WHAT DOES IT MEAN?

Leaking transmission fluid will likely be somewhat transparent red, pink, or gold, perhaps redish-brown in color. If the leaking transmission fluid is dark (brown or black) and/smells burnt you may have a bigger problem, have it checked. Leaks are usually caused by a compromised gasket or seal. Have it fixed before it gets worse and causes more costly damage.

Any leaks should be checked by a mechanic. Thin green or yellow transparent liquid means your radiator is probably leaking. Brown viscous fluid is probably motor oil or possibly transmission fluid that is bad. Transmission fluid is usually red, pink, gold, or if old brownish-red in color and somewhat transparent. If it is dark brown or black and/or burnt smelling it probably needs to be replaced along with the filter. It would be a good idea to have it checked by a professional.

HOW OFTEN SHOULD I HAVE MY AUTOMATIC TRANSMISSION SERVICED

Many things factor into how often you should have your automatic transmission serviced. As always, the first place to check is the owner’s manual. That said, how you drive, where you drive, the climate, and whether you are towing all can contribute to how often you should have your transmission serviced. Lots of stop-and-go city driving, heat, driving in the mountains, and towing all contribute to faster breakdown of transmission fluid and require more frequent servicing. 30,000 miles or every other year is a general service interval to change your transmission fluid and filter.

COMMON AUTOMATIC TRANSMISSION PROBLEMS

If you are experiencing any of these problems you should have your automatic transmission vehicle checked out. Remember the function of a transmission and that an automatic transmission is shifting the gears of the car without your help.

  • Hard, loud, abrupt shifting between gears
  • Transmission fluid leaks under your vehicle
  • Rhythmic knocking
  • Grinding when changing gears (when the car is changing gears, not the gear selector)
  • The engine speeds up without changing gears to compensate
  • The car is slowing; but, the engine is not
  • The engine is racing, but you are using the breaks
  • A clunk sound when you put the car into gear
  • A significant delay of the car speeding up when you press the gas peddle hard
  • Irregular sounds like the car is shifting when you are going at a steady pace