When Should Your Car Have a Transmission Flush?
The transmission fluid in your vehicle is a critical part of the health of your transmission, providing hydraulic power and lubrication necessary for the intricate parts to operate properly. Over time, this fluid gets dirty or breaks down through heat, and needs to be replaced with a transmission flush. Not only does this help keep your car's transmission running at its best, but it can also extend the life span of the transmission itself.
What happens during a transmission flush?
The “simple” method of replacing the transmission fluid (often done at home) is to let the old fluid drain out and pour new fluid in to replace it, not entirely unlike an oil change. However, this method tends to leave residue in the line which can compromise the new fluid. A more accepted method is to do a full flush at a trusted auto repair shop, where the mechanic attaches the vehicle to a machine that uses the vehicle's own transmission pump to gently flush out the old fluid while pumping in new fluid simultaneously. If the line is particularly dirty, the mechanic may run a solvent through the line first to clear out debris before the new transmission fluid is introduced.
When should you have the transmission flushed?
Most manufacturers recommend a transmission flush every 30,000 miles or every couple of years. However, there are other times besides these intervals when a flush might be a good idea. These include:
- When the fluid is dirty or “burnt.” You can check the transmission fluid via the dipstick in the engine. Clean transmission fluid looks bright red and clear, accompanied by a sweet smell. If the fluid looks dark and opaque, or smells “burnt,” it probably needs to be replaced.
- When there are symptoms that the transmission isn't running properly. These may include hesitating when shifting into gear; odd noises; slipping gears; or experiencing vehicle surging forward or backward while driving. While these may point to more serious problems with the transmission, a flush may make the car run more smoothly for awhile.
Can a transmission flush harm the transmission?
There is some speculation that a transmission flush can do more harm than good by dislodging debris along the transmission line. However, this usually only happens when the auto shop is using a machine that forces the fluid backward through the system, instead of the gentle flush method we described above. That being said, if your vehicle has gone 100,000 miles or more and you've never done a transmission flush, there's a greater chance that a flush will cause the transmission to fail, and your mechanic may advise against it.
Preventative maintenance, not a cure
Just as a reality check: flushing the transmission fluid won't fix existing problems with the transmission. If you notice symptoms like erratic shifting or grinding noises, your transmission may already be damaged, and while flushing the fluid might delay transmission failure, it won't prevent it. A trusted specialist will be able to advise you whether transmission repairs are needed.
In Olympia and the South Bay, Lloyd's Automotive and Transmission Specialists have been providing reliable auto repairs and service for more than 50 years. They can be reached at 360-357-7422 for questions about a transmission flush or any other automotive service or maintenance needs.
Written and Published By MORBiZ