by Pat Goss
So you don’t think there’s a reason to buy that special transmission fluid for your automatic transmission? Well guess again. Automatic transmission fluids are tailored to the operating characteristics of a specific transmission. Now what we’re really talking about here is a factor known as coefficient of friction. Now if you think of that as being like sandpaper. Here we have course sand paper, medium sand paper, and fine sand paper. And if you run your hands over them, you can feel a real difference. Certainly the course is more grippy than the fine.
Well, inside your automatic transmission you have clutches. In this unit, we can see them in this area and up here. Well these clutches, are similar to what we have right here. These are actually automatic transmission clutch discs, and if you get the wrong transmission fluid in your automatic transmission, what can happen is really simple. Suppose your transmission takes this really grippy high coefficient transmission fluid and you get some generic stuff that is really fine with a low co efficient of friction, every time these clutch discs are engaged you’re going to get slippage. Slippage means heat, heat means a shorter life, so over a period of time you’re going to shorten the life of your transmission. But you say well, no that’s not the case, maybe I’m going to get some of this that’s really grippy and mine doesn’t require it, but that can’t be bad can it, well yes it can. Because it causes the clutches to engage with a shock, you get a firm shift. And over time that shock load on the clutches causes this friction material to crack and finally fall off and you have to buy a new transmission.
Oh, and also don’t let some shop tell you that oh, I have a chemical that I can put into generic fluid and it converts it into the proper fluid for your transmission. Don’t buy it because it often does not work. Spend an extra buck or two, get the transmission fluid that is designed specifically for your car, and it will save you money in the long run. And if you have a question or comment, drop me line right here at MotorWeek.