Jerking from your 2017 Toyota Avalon's 6-speed automatic transmission indicates shift quality problems that range from minor adaptations to mechanical wear. The Avalon uses the U660E transmission, a proven design also used in Camry and other Toyota vehicles. Understanding what's causing the jerking helps determine appropriate action.
Types of Transmission Jerking
Jerking during upshifts: Shift timing or pressure issues. Jerking during downshifts: Often torque converter clutch related. Jerking at low speeds: May involve 1-2 shift or torque converter lockup. Jerking during deceleration: Often TCC cycling or coast-down shift issues. Random jerks: Possible solenoid or pressure issues.
Common Causes
Degraded transmission fluid loses friction-modifying properties, causing harsh engagement. Shift solenoid issues affect shift timing and pressure. Torque converter clutch problems cause shudder or jerking. Valve body wear affects hydraulic control. Adaptive pressure has increased due to clutch wear.
The U660E in Avalon
This transmission is generally reliable but not immune to issues. The luxury sedan duty cycle—city driving with frequent stops—can be demanding. Fluid condition significantly affects shift quality. Regular fluid maintenance helps prevent many issues.
Diagnostic Steps
Check transmission fluid level and condition. Note which specific shifts jerk—1-2, 2-3, TCC engagement, etc. Scan for transmission codes, even pending ones. Monitor shift adaptation values if possible. Compare shift feel when cold versus warm.