Jim, I am only 12 months late in replying. I have just bought a new RAV4 I4 3 months ago and have been pondering the same questions as yourself about whether to fit a transmission cooler for towing. Yes the RAV here is approved for 1500kg. In the owners manual Toyota indicate that is 1500kg braked and from memory think 600kg unbraked. Most passenger vehicles are approved by the regulatory bodies in each state to tow up to their own weight, commercial vehicles have different requirements. Now back to the transmission cooler. I emailed Toyota here in Aus ( not the dealer) and Toyota said that no additional cooler is necessary when towing up to the approved load. I monitor the fluid temp with Scangauge as there is a temp sensor built into the transmission. Am I concerned, Yes given the fluid temperature I am seeing so I will be fitting an additional cooler. I hope this helps. Barry
