Toyota Avalon 2008 Quick Reference Manual page 157

Changing shift ranges in "S" mode
Shift the shift lever to the "S" mode driving position and operate the
shift lever.
The initial shift range in "S" mode is automatically set to "5" or "4"
according to the vehicle's speed. (→P. 132)
Shift ranges and their functions
n
l You can choose from 6 levels of engine braking force.
l A lower shift range will provide greater engine braking force than
a higher shift range, and the engine revolutions will also
increase.
2-1. Driving procedures
Upshifting
Downshifting
2
131