This is what I have done regardless of what the manual says. I usually don't rotate the spare because it is mostly wore out, but still a good spare. One time I rotate the outer right dually with the right front. Likewise with the left outer to left front. Inner dually to inner dually. Next time I rotate the right inner dually with the right front. Likewise with the left tires. Then outer dually with outer dually. I use four heavy duty jack stands, a 6 ton bottle jack and a corded electric impact wrench. I do this maybe every 7 to 8,000 miles. It's best to get the whole truck off the ground and use an impact wrench, otherwise you'll be at it all day.