What is a Transmission Flush?

As part of most standard 30,000-mile maintenance procedures, it's recommended that you get a transmission flush. But what is it? Most of the other items in the 30/60/90k service suites make a lot of sense but the transmission flush is a often very vaguely defined for the average driver, and most drivers don't quite know what they're paying for getting one. Let's fix that right now!

What is the Procedure?

A transmission flush is a procedure done on automatic transmissions, which have their gears suspended in a hydraulic fluid called, rather plainly, Automatic Transmission Fluid. As your transmission does its daily work, this fluid becomes very hot and can burn, turning it from a kind of pinkish color to brown and eventually to a blackish color if left too long in the transmission. As it burns, its ability to lubricate decreases -- and keeping the hundreds of moving parts of an automatic transmission lubricated and separated is one of its primary jobs, besides using hydraulic pressure to advance the gears. When the fluid wears out, you have two options to replace it -- you can drain or flush the fluid.

Draining the fluid is just what it sounds like: the transmission casing is opened and the fluid flows out, then you replace it with new fluid. This is simple, but not all of the old fluid drains out, much of it clings to the interior parts of the transmission. A transmission flush uses a machine to suck the old fluid out while at the same time pumping in new fluid -- what this does is wash clean all of the interior parts that would still be coated with old fluid if you left it up to gravity alone. A flush assures that the ATF in your transmission is 100% new and that all the built-up residues are removed along with the old fluid.

Is There Ever a Reason Not to Get a Transmission Flush?

There's two reasons: either you don't need one yet or it's too late for one. ATF is designed to last for a long time, and you don't need a flush more than every two years or 30,000 miles. Oil changes should be done more regularly, but automatic transmissions are a sealed system and less affected by the residues of combustion that the engine has to deal with.

If your ATF has flakes of metal in it, don't get a flush -- get a full transmission rebuild. Flakes in the fluid indicate that the physical, metal components of your transmission are failing and need to be replaced. A flush at this stage of transmission decay may cause the transmission to fail completely. Take your vehicle immediately to an auto repair professional if you discover it's exhibiting this symptom.

For Southern California residents, the technicians at Covina's Hye Tech Auto Repair and Diagnostics are experts at providing fast and efficient routine maintenance like the transmission flush. They'll tell you if you need one and if you don't, when you're likely to. Plus they can handle any of the more complicated issues that can arise from transmission wear. Call them today at (626) 332-5452 and get your car running as smooth as the day you bought it.

Hye Tech Auto Blog

Written & Published By MORBiZ