Ditto for automatic transmission fluid, which some manufacturers say can last 100,000 miles in normal use. But what about ...

Trans fluid breaks down and wears out ... your best bet is a transmission cooler, which is like a tiny radiator just for your gearbox. A lot of cars come with them, especially high-performance ...

This component is often built into the radiator, where it can transfer excess heat from the transmission to the outside air. However, your car or truck’s OEM transmission fluid cooler may not ...