Automatic transmissions have been around since the 1940’s when GM first introduced its “Hydramatic” drive system. This system got deployed in several of the world war two tanks notably the M5 Stuart and M24 Chaffee, and this brought further refinements. After the war the auto industry went through a massive boom and soon automakers were either licensing or bringing out their own flavor of the automatic transmission.
Demise Of Stick Shift
Since then autos have slowly been eating away at the stick shift market share and today less than 2% of all new vehicles sold in the US are manual transmissions. The current trend is surely indicating the demise of the stick shift. Yet some of the purists will argue that not having a stick shift detracts for the driving experience of a car. Personally, we think that a responsive paddle shifter gives you all of the control of a stick, with the convenience of the automatic. These days they are pretty good at fuel economy too. We digress, the point of this article is not to persuade you that 21st century technology has its good points, but to look at the key differences in vehicle maintenance between an auto and stick transmission.
Firstly, let’s discuss their technical differences.
Manual transmissions are pretty conventional across manufacturers, all consisting of a single case (for a front or rear wheel drive car) containing five or six forward gears, one reverse and possibly a differential. The gears are usually helical to eliminate noise and are coupled to the differential on one side and via a wet/dry clutch to the engine on the other. The case is generally filled with a high quality 90 grade gear oil.
As you might have deduced from this, most manual transmissions are pretty robust and require little maintenance. If you have an older track car like an E36 BMW it is a good idea to change the transmission fluid (gear oil) once every two years. In the case of your daily driver, once every seven years is fine.
Automatic transmissions are an entirely different animal. This is chiefly because there are so many different types. Three of the most common ones are continuously variable (CVT), torque converter drive, and Direct Shift Gearbox (DSG). All of these employ different coupling systems, different types of hydraulic or (more commonly today) electro-mechanical control systems and different gear combinations. Discussing each type in depth would take another article. The one common denominator is that they all require careful maintenance. The older torque converter systems pump fluid through the gearbox, and as such have a fluid sump, filter screen and gasket that need servicing at least every two years. On Volkswagen DSG or Porsche PDK transmissions, an oil service is required every 40 000 miles or two years, whichever comes first. Subaru CVTs require oil changes every 60 000 miles.
These services consist of more than just an oil change; the transmission is thoroughly inspected; leaks are repaired and filters cleaned or replaced. Adhering to them is critical if you want to ensure the longevity of your transmission and save on costly repairs at a later stage. If you are unsure of when last your transmission was serviced, check with your manufacturer’s guidelines or pop in to Foreign Affairs Motorsport for some friendly advice from our ASE certified team.