That's what I was thinking this dealership that I have been talking to said the 99 4runner Highlander I have been looking at had the DIFF lock but the place where the DIFF LOCK button normally is, there is the security light. I mainly wanted it for the gear ratio I don't plan on doing any major wheeling but I wanted to put 265/75r16's and black rock steel Type D wheels on it but I figure with the stock 4.10's it'll put to much strain on the Transmission.