Automatic transmissions get substantial benefit from proper service, but many transmission shops encourage a very profitable up-sell instead. A transmission flush does the vehicle little good and may cause it harm.
The right way to do a transmission service starts with a test-drive of the vehicle. After that, the transmission should be visually inspected for leaks and external problems. Generally, a transmission will have a removable pan and underneath that will be the filter. The fluid should be drained. Then the pan can be removed, and the filter can be replaced. Finally, the valve-body bolt torque should be checked, and the transmission can be reassembled, filled with the proper fluid and given a follow-up test-drive.
The problem with doing the infamous "transmission flush" is that it involves nothing more than removing the cooler lines with the engine running. Fluid runs out and more is added. When a set amount has been added, the lines are reinstalled. What's missing is the inspection of internal components and what is worse; the filter is not replaced or even inspected. A filter that is clogged or restricted by metal shavings can be a cause of slippage. The danger is compounded because draining out and replacing the fluid can dislodge debris that will further reduce the amount of fluid that passes through the filter.
Transmission failure is frequently caused by slippage. A common cause of slippage is low pressure, which can be the result of a restricted filter. A transmission flush does not replace the filter and may stir up debris that further restricts it. By itself, transmission fluid rarely causes problems, unless the wrong fluid is used.
"Flushing" is profitable for transmission shops!
A transmission flush machine can cost thousands of dollars and for some shops it's a real money-maker!
Shops usually pay their employees based on hours worked and highly-skilled workers are paid more than those with less experience. When you agree to a "Power Flush" on your transmission, a low-skilled tech can plug the flush machine into your transmission and walk away to do something an another vehicle, while the transmission is being flushed. The filter doesn't get inspected and pan gasket doesn't need to be replaced. The only expense for the shop is the fluid (which you pay for at a marked-up price) and the few minutes of labor needed to hook up and then disconnect the flushing machine. Another concern is that a universal fluid, possibly containing a solvent, might be used, instead of the fluid specified for your vehicle.
Commonly the color of the transmission fluid is used to sell a "Power Flush" on a transmission. This can be very misleading, because just looking at color does not show the fluid condition. Transmission fluid can vary widely in color, even when it's new. It's normal for fluid to darken over time unless the fluid is black. That suggests that it is burnt and a problem has already occurred within the transmission itself, in which case it is too late for a service and repair will be needed.
When you bring your car, truck or van into our shop, we will do a free test drive to get a feel for how it is shifting. Next we talk to you about the sypmtoms you have noticed while driving it every day. If your transmission does need repairs start be inspecting the unit for leaks and examine the filter to see what's going on and then we use the latest technology and our decades of experience to pinpoint the problem.
Waves offers a vast set of services and solutions that help you achieve the desired result.