Toyota SIENNA 2009 Quick Reference Manual page 351

Towing with a sling-type truck
NOTICE
To prevent body damage
n
Do not tow with a sling-type truck, either from the front or rear.
Towing with a wheel-lift type truck from the front
2WD models
Release the parking brake.
I n f o r ma t i o n P r o v i d e d b y :
5-1. Essential information
5
497