I tow a 2002 4Runner 4WD and must use a drive shaft disconnect. As Gary said above, Remco is THE place to go. http://www.remcotowing.com/ As I understand it, all electronic 4WD vehicles must use a drive shaft disconnect. Mine has been trouble free since 2002 - with about 40K miles towing between two different coaches and several times across the US. That is until today! I had trouble getting the drive shaft to connect after a long tow. Found out that two small parts called shift blocks are worn and won't let it fully engage. Remco is sending the two parts ($40) and about 30 minutes will be needed to replace them. Not bad for that long.
