I don't have any half axles out, but I am quite sure the half axles in a 2 ton are larger in diameter than the 1 ton. If you have a 5.43 (38-7) you are very fortunate. They are hard to find. I would put some larger tires on it and be done with it. It will go as fast as you want to go. I looked in the parts book, and there are 2 pages of different half axle sizes listed, so it is very unlikely the change you want to make is possible.