Dark brown or black fluid with a acrid smell means it's overheating.

Additives prevent sludge buildup inside the valve body. Quick Maintenance Tips

Most cars need a flush every 30,000 to 60,000 miles.

Do this while the engine is warm and idling.

Checking your transmission fluid is a quick way to gauge your vehicle's health. While it shouldn't have a "taste," its smell and appearance tell you everything you need to know. The "Taste" Test (Visual and Olfactory)

If you feel metal shavings, internal parts are wearing down. Why Fluid Health Matters

It whisks heat away from sensitive internal components.