from Goss’ Garage by Pat Goss

Modern automatic transmissions can be traced back to 1904 when the Sturtevant brothers of Boston developed a clunky, inefficient, failure-prone centrifugal gearbox. An inauspicious beginning and nothing like today’s transmissions which shift smoothly, deliver great fuel economy and exceptional durability. However, the sophistication of today’s transmissions means repairing or replacing a broken one now costs more than a whole fleet of cars did back in 1904. Transmission repair or replacement can be mind-numbing expensive these days.

To complicate things long term financing may mean you owe more than your car is worth so you can’t afford to trade and another maxed-out credit line looms. Although repairs are expensive preventing them is cheap and makes the most sense. Maintenance used to mean dropping the transmission pan, replacing the filter and refilling with fluid. But that was a long time ago. Today proper service is very different because the old method can actually shorten rather than increase the life of today’s transmissions. That’s because the old method didn’t clean anything inside the transmission and it only replaced about a third of the fluid.

The old process leaves the transmission as dirty as it was before the process began and still filled with two thirds old oxidized fluid. Problem is, new fluid doesn’t always mix properly with the remaining old dirty fluid. Plus without any cleaning the new more-detergent fluid softens deposits allowing fine particles to circulate through the transmission causing wear. Some of the dirt particles are so small they pass right through a transmission filter if yours even has a filter as many now opt for a filter-screen instead.

Today, proper transmission service means flushing, which significantly extends transmission life. Unless you feel dirt and varnish is somehow beneficial to mechanical devices I suggest you flush your transmission. The first step in flushing is adding chemical cleaners followed by running the car to soften and dislodge all the oxidized varnish and dirt built up in the transmission, torque converter, cooler and cooling lines.

Then the car is connected to the transmission flush machine which captures and quarantines all the old fluid coming out of the transmission and sends fresh new fluid back into the transmission. In a transmission flush all the bad stuff is quarantined outside the car, while in the old method all the bad stuff stays in the transmission. Plus flushing replaces nearly 100% of the fluid where the old method only replaced 25% to 33%.

When it comes to the fluids in your car there is nothing more beneficial than cleanliness. So a flush should be done every two years or 24,000 miles never more than 30,000 miles. Also, contrary to what your dealer may have told you, there is no such thing as a fluid that lasts the life of the vehicle. Nothing lasts forever, all fluids wear out and when the fluid wears out the transmission soon follows. There is also no such thing as a completely sealed transmission, they can all be flushed with proper adapters.

Beware of shops that sell fluid exchanges and call them flushes. A fluid exchange is quick and highly profitable for the shop but a waste of your money. Fluid exchanges can be done in the service lane in about half an hour where a flush requires about an hour and a half. One way to be sure you’re getting the real deal is to look for a shop that uses BG products and equipment like I do.

I know the economy is tight, but avoiding preventive maintenance is truly a false savings. Metal doesn’t understand economics and if not kept properly lubricated fails. Fixing a broken car always costs a lot more than the service to prevent the failure. Also shop carefully as the bad economy means shops are desperate for dollars to survive and desperation sometimes pushes good people to do bad things.