Toyota Sienna transmission cover cracked while driving, leading to fluid loss and transmission replacement on Toyota Sienna

Some Toyota Sienna owners report experiencing significant transmission issues, including shifting delays, grinding sounds during acceleration, and burning smells while driving. These problems can lead to gears slipping and jerking movements, as well as transmission noise even when in neutral. Additionally, owners of the 2017-2018 models have reported software problems affecting engine and transmission performance. While the 2021 and later Sienna models feature a problem-free eCVT transmission, those manufactured between 2011 and 2020 have faced challenges with the 8-speed UA80E automatic transmission, which can result in harsh shifting and check engine lights due to installation errors. In cases where the transmission cover cracks, fluid loss can occur, risking severe damage to the transmission system; thus, prompt attention from a professional mechanic or Toyota dealership is crucial to prevent costly repairs or replacement.