This "mechanic" is full of sh*t! I have worked for lexus as a tech for 12 years and have seen only 3 rear wheel drive transmissions fail. I own a 1990 ls400, 1992 sc400, and a 1997 gs300, none with any type of transmission issue. All vehicles have over 100,000 miles, the ls400 having 278,984 miles. Never a problem.