About 85-90% of passenger cars today rely on automatic transmissions to transfer kinetic energy from the engine to the driven wheels. Almost three quarters of those comprise of standard automatic transmissions with torque converters while the second largest (and ever growing) type happen to be CVT-based (Continuously Variable) transmissions. The third largest group falls under the direct shift type which is kind of like a hybrid auto-manual tranny that incorporates a robotic mechanism to switch in and out of cogs with the help of friction clutch plates much like a manual gearbox. This third type usually employs 2 clutch plates to achieve lightning quick gearchanges, even faster than a manual gearbox ever could.
Automatic transmissions, regardless of whichever configuration, requires some attention to keep them running like clockwork and without complaints. When it comes to maintenance, many car owners take very good care of their engines and paintwork, but oftentimes neglect their gearboxes which are expected to perform quietly in the background, neither seen nor heard. But used car dealers are very afraid of broken or abused gearboxes more than badly maintained bodywork, so it does pay dividends to minimize wear and tear in that vital component, as a quick test drive by any seasoned dealer will reveal any problems instantly which invariably leads to a slashing of thousands off the offer price. So with that, let’s take a look at some of the ways that we could prevent disaster from happening under our care.
Auto transmission fluids
Irrespective of configuration, every gearbox requires sufficient and quality lubrication. After all, every component within the gearbox is made of metal, which hates coming into contact with another metal. A film of oil prevents metals from abrasion and eventual catastrophic seizure, so you’re well advised to stick to the manufacturer’s recommended change interval religiously. Even better, change the transmission fluid earlier as there’s never anything wrong in treating your car as well as you could. Some may argue that it isn’t necessary and we should just stick to what the carmakers recommend, but here I’d like to bring to mind a case from the past where a certain manufacturer recommended just one annual oil change for their “unbreakable” engines, which led to many frustrated owners with sludge in their broken engines in places where fresh oil used to flow.
Our punishing climate and overly optimistic construction industry has led to severe degradation of air quality which in turn forces us to drive in the harshest of conditions on a daily basis. Transmission fluids tend to break down faster under extreme operating conditions, so changing out the lifeblood of your car’s tranny earlier than recommended will ensure a smooth tranny for years to come. Many mechanics out there even recommend installing transmission coolers on older vehicles which essentially adds a radiator up front that cools the fluid down as you drive. The problem with that is you are altering the flow characteristics of the transmission cooling system by introducing an additional load which may strain the system. Also, adding a tranny cooler means you now need to factor in an additional liter or so of extra fluid at your next fluid change. So factoring in the cost of the cooler and its potential hazards, I’d rather just change out the fluid more often. Aside from the fluid, regular checking of the oil pan, gaskets and ATF filter are also recommended.
Transmission: Changing Directions Abruptly
Today’s society tends to always be in a hurry scuttling here and there. Over the years, I’ve observed the driving habits of friends and acquaintances and one thing many of them tend to do is they don’t give their transmissions time to switch cogs between R and D. Have you ever noticed a friend or even yourself being in a rush situation, where you quickly reverse to try and get out of a parking lot, and before the car comes to a complete stop you switch from R to D and immediately step on the gas? Or, sometimes, when you’re about to come to a complete stop, you switch into Reverse and immediately step on the gas to change the direction of your car? Guess what, your gearbox is in pain! Please don’t do that, give your gearbox a second or two to fully engage the proper cogs before slamming the throttle. Otherwise you’ll end up with a clunky gearbox after a year or so.
Shifting to P before Applying Parking Brake
This is one of the biggest causes of transmission degradation and it’s something almost 80% of the people I know are guilty of. When coming to a stop on an incline or decline, many people tend to immediately set the car to Park before engaging the parking brake. Heck, some people I know don’t even bother to engage the parking brake, instead letting the parking pawl (a pin that holds the tranny in place) do the job of keeping more than a ton of metal from sliding forwards or backwards.
That’s fine if you’re on a perfectly level road (but still not recommended), but if you ever park on a slope, you are well advised to put the stick into Neutral first, then apply the parking brake. Notice how your car ever so slightly moves in the direction of the slope before being completely held in place by the parking brake? Once you’ve done that, then only should you engage Park. This leaves the parking pawl well alone and lets your car rely on the parking brakes to keep the car stationary like how the engineers designed it to do.
Also, before moving off, you should also take care to disengage from Park before releasing the parking brake. Have you ever experienced releasing the parking brake, only to realize that the car won’t move because it’s still in Park? Have you ever experienced shifting out of Park then and noticed a loud clunk? There you have it.
In case some of you didn’t know, automatic transmissions do need time to warm up too, just like the engines that drive them. So for those of you who start up the car, light up a cigarette and wait 30 minutes for your car engine to warm up before driving off violently, well guess what, your gearbox is still cold as a fish! So driving off gently for the first 10 minutes to let the engine warm up properly also pays dividends in that your autobox also gets a nice and warm wakeup call before being pressed into active duty. The only time that you should disregard this practice is if your life depended on it, bearing in mind that your car has no choice but to take a beating for the team.
Shifting to Neutral and Coasting to Save Fuel
This may not mean anything to Millennials, but there was a time when old timers who drove manual cars tended to disengage their gears on a downhill run in order to save some fuel. Back then, when all cars were of the carbureted variety, there was no way to cut off the fuel while driving downhill, so by disengaging the gears one could effectively coast a little bit faster with less drag, while the engine was kept at idling speeds to keep the air-conditioning and other auxiliaries running. There was some truth back then, but today’s cars are equipped with state of the art fuel injection systems that efficiently regulate the use of fossil fuels.
So, when facing a downhill run and with the gears engaged and with zero throttle input, the car’s computer will recognize the scenario and immediately shut off the fuel system, which effectively means that your car’s forward momentum as a result of downward gravitational forces are actually keeping your engine and peripherals running without a drop of fuel! How cool is that? Why is this relevant in an article about gearboxes?
Well, those in favor of coasting (even though it burns more fuel as a result) may not realize it, but at the end of the slope when you need to reengage the gears, you are causing unnecessary stress to the gearbox by forcing the autobox to match the speed of the wheels that are coasting at high speed. Before reengagement, the car’s ECU does not have a means to control the speed of the cogs within the gearbox to speed up to match the driven wheels as that is a purely mechanical function, so in the process there will be some unnecessary wear. Not to mention, before coasting, your gearbox would’ve been operating at its optimum operating temperature while having the engine operate the pump that circulates cooled fluid through the system. If you coast while the engine is kept at idle speeds, the flow rate of the fluid may not be able to match the cooling requirements of the gearbox at that instant, and this may degrade the fluid prematurely.
Not Towing the Driven Wheels
It may not happen to everybody, but if in the unfortunate event your car needs to be towed, always insist on towing the driven wheels, i.e., if your car is front wheel drive, never let the tow truck guy tow the rear, leaving your driven wheels on the ground. The inverse is true for rear wheel drive cars where you always tow the rear off the ground and not the front. As mentioned in the earlier paragraph, automatic transmissions circulate tranny fluid via the rotating engine. If the engine is stalled, fluid will cease to flow. And even in Neutral, the planetary gears in an automatic transmission are all fully engaged but merely prevented from transmitting the power to the wheels via a set of clutch packs. If the driven wheels are rotating, the gears in the autobox are rotating too, so if the fluid isn’t moving, the autobox will heat up without proper lubrication. Very bad idea. If there is no way to tow the driven wheels for whatever reason, always insist on a flatbed tow truck.
We hope this article will help you get more miles out of your precious ride. The automatic transmission in your ride is one of the most important mechanical components that is the last link between your right foot and the tires that doesn’t really need a lot of constant care but just good practices to keep it in tip top shape.
Text: Greg Yang