Assume (always dangerous) that your Highlander is first generation.
Meaning it is derived from the Camry...so think of towing with that,
a Camry
Second gen Highlander is derived from the Odyssey
Stuff like the MTWR (Max Tow Weight Rating), etc are derived from the
'curb' vehicle. So if yours has an automatic, AC, etc...those ratings
do not apply and are lesser by the weight of the stuff over and above
the "curb" vehicle
Oh...no tow option...then even less rating until you add the main
component if you have an automatic...an external automatic tranny cooler
I never say sure or no, just provide you the OP with metrics to figure
it out yourself...as there is only one person responsible for the
setup...that is the driver