Replacing automatic transmission fluid is both a vital maintenance as well as a potentially useful diagnostic step. Here's why service personnel should never underestimate the value of fresh fluid.
The overwhelming majority of vehicles on the road are equipped with automatic transmissions. Automatic transmission fluid, commonly called ATF, is the lifeblood of these complicated devices.
Now, motor oil's primary job is lubricating moving parts. It also cools those parts to some extent. Obviously, coolant cools the engine.
But ATF arguably works harder than these other fluids because it does more than just lubricate and cool. You see, ATF transfers power from the engine to the transmission and activates components such as bands and clutches.
To grossly simplify, work equals heat. Heat eventually takes its toll on any automotive fluid — especially ATF.
What's more, ATF typically contains a lot of cleaning agents that are crucial to the longevity of the transmission. (Many technicians refer to these as "detergents.")
On the one hand, we could be discussing a simplistic, fully mechanical, two-speed automatic transmission from the 1960s.
Or we may be talking about a computer-controlled, six-speed modern marvel of a gearbox. Whether the design is basic or advanced, worn-out and dirty ATF has been a common cause of premature automatic transmission failures.
What's more, ATF maintenance largely has been out of sight, out of mind to a typical motorist.
For years, trusted sources have told me that most motorists don't request an ATF replacement nearly as often as an oil change — if they ever ask at all. So, it's likely that service personnel will have to actively promote the value of this seemingly forgotten maintenance.
Experience shows that some automotive service facilities sell transmission services more effectively than others do. Sadly, some tire dealers and service shop operators don't bother to sell any ATF replacements whatsoever.
Mind you, some automatic transmissions manage to endure miles' and years' worth of use and abuse.
On the other hand, many transmissions do not survive. It's been a revealing exercise to look over the shoulder of a trans specialist as he or she "autopsies" a series of failed automatic transmissions.