Durability, reliability, and trouble-free dependability are all hallmarks of Toyota vehicles. But it is not immune to certain issues that crop up, especially after the miles pile up. It uses many different automatic transmissions across all of its lines. Sienna minivans and Highlander SUVs with 8AT transmissions have reportedly seen a rise in issues. 8AT transmission issues resulted in a class-action lawsuit filed in 2020. Over a million Toyota vehicles are part of that lawsuit.

What transmission problems are Toyota drivers having?

The problems are explained in both the lawsuit and also consumer complaints with the National Highway Traffic Safety Administration. It alleges loss of power or the ability to accelerate. Another issue is transmissions being stuck in one particular gear. The complaints include the 2017 to 2020 Highlander and Sienna, the 2018 to 2020 Avalon sedan, and the 2019 RAV4. 

Other complaints involve rough, delayed, or sudden shifting, lack of acceleration from a stop, shuddering, abrupt loss of power, and early transmission failures. Some Sienna owners describe deceleration while going into a corner when in Eco mode. Owners say they cannot find a way to defeat the Eco mode, according to Vehicle History.

Which Toyota models have transmission problems?

So far, Toyota nor the NHTSA have initiated a safety recall. In 2020, Toyota upgraded the transmissions in models that included the Avalon, Camry, Corolla, Highlander, Matrix, and RAV4. This helped to improve efficiency. 

Also, a shift flare can occur during cold start shifts from third to fourth gears. The transmission will slip slightly, followed by a slight increase in engine speed. Causes range from transmission control module software to a weak battery or corroded battery terminals. Also, replacing broken-down fluid can help you avoid some of these problems.

Do this to add longevity to your transmission

Once mileage adds up, problems can range from internal wear to valve body and electronics failures. In general, many of these issues can be remedied by simply keeping transmission fluid levels up. Especially during long driving periods, the fluid can start smelling burnt. If that is the case, the transmission may be overheating. Again, transmission levels may be low, or it could be the transmission cooler has plugged-up lines. 

The good news is if your Toyota is experiencing problems and was built in the last few years, the warranty covers them. Toyota will address the problems on an individual basis at one of its dealerships. You can also go to the Toyota Customer Experience Center for more information. Finally, you can also go to the NHTSA website for information concerning recalls.