I have a Highlander with the tow package. The RVA4 tow package is similar to the Highlander’s. The tow package consists of heavy-duty radiator with an engine oil cooler, 200-watt fan coupling, transmission oil cooler, 150 amp alternator and "pre-wire harness." Toyota does not list the tongue weight
limits for the Highlander, only towing capacity. With the towing package, a Highlander can tow up to 5,000 pounds. Without the tow package, the limit drops down to 2,000 pounds. The Highlander is a '08 model earlier models had lower limits. Hope this helps.