Why a transmission flush is never money down the drain
18:06 |
| New vs. old: The transmission fluid on the left is the color you want to see. The sample on the right has seen better days. |
When a transmission
fails, it’s usually a long money affair to fix it. But you can fight back:
flush.
Automatic
transmissions contain a maze of passages through which transmission fluid must
pass to ensure smooth gear-shifting. Unfortunately, transmission fluid
deteriorates over time, turning from its original bright red to gray, brown or
even black as dirt and metal particles from wearing gears contaminate it. When
this fluid isn’t flushed regularly or thoroughly, it’s unable to build up
sufficient hydraulic pressure to properly shift gears.
It’s important to
distinguish between a transmission service and a transmission flush.
Typically, a simple service involves draining—not flushing—the system, which only replaces some of the fluid. This means new fluid will be mixed in with old, quite possibly contaminated, fluid. During a service, some disassembly is required—fluid-pan removal and filter cleaning or replacement—increasing the risk of human error.
Typically, a simple service involves draining—not flushing—the system, which only replaces some of the fluid. This means new fluid will be mixed in with old, quite possibly contaminated, fluid. During a service, some disassembly is required—fluid-pan removal and filter cleaning or replacement—increasing the risk of human error.
A flush, on the other
hand, doesn’t require disassembly and will replace all the transmission fluid.
The filter won’t need replacement since the pressure used during flushing is
sufficient to clean it.
A service typically
only replaces a few quarts of Tran’s fluid that’s found in the body of the
transmission. However, the typical transmission holds roughly 12 quarts, much
of which is found in the torque converter, plus lesser amounts in the Trans
cooler and cooler lines. Without a flush—which uses pressure to remove every
drop of old fluid—the bulk of old fluid will remain inside your vehicle’s
Trans.
One of the biggest
benefits flush offers is that it can uncover latent transmission-system
problems, including compromised seals and cracks, before they have a chance to
turn into big-money repairs.
