The purpose of transmission additives can vary among different products. However, the general idea is that by adding them to your regular transmission fluid, they can improve the efficiency of your car’s functions. Some additives claim to soften and condition old pressure seals, while others promise to stop fluid leaks in the gearbox.

But do these additives actually deliver on their claims? They do, at least temporarily. When initially added to your car, additives can provide a slight improvement in its performance. They can reduce gear slippage, unclog filters, and help reposition gears, among other benefits. However, the problem lies in their longevity. These additives often deteriorate quickly, breaking down under the high heat generated by the gearbox’s components. As a result, you would need to open up the gearbox and add the additives again to maintain their effects. In fact, this can make the task of topping off your fluid more burdensome instead of reducing it.