The red color is from a dye that is added to the fluid. Over time the dye breaks down.

If the fluid runs too hot it also gets dark in color. Even under normal conditions it will get darker, but not much past a light brown. The harder part of the color change test is knowing what is normal wear and tear or if it got too hot.

The fluid on my Raider has never gotten to hot, but after five years, it does have a light brown color to it.

A burnt smell is always bad. If in doubt, fresh fluid is good preventive maintenance.

Kevin

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...