It's not about getting them to high mileage, it's the fact that if you want to have any fun with it on the trails, it's so much better, and more reliable with the dual range. You can do things and have more fun than you ever thought before!! 3AT will go many miles, it's just if you actually use the 4WD much, it will burn out the rear transfer clutches, then you will only have FWD, and the low end torque is terrible!!!! And all this is multiplied when you have bigger tires!! You have done a great job on your cars though!!!