One thing not mentioned by Wayne in his article, or his book (the last time I checked) was some other differences between the SD rear brake axle (OTC) and the factory JL8 package. Wayne's article mentions the axle diameter and bearing size, but doesn't reference the difference in the POSI carrier used in the two. The JL8 rear used the same posi carrier in terms of number of plates and spring pressures as other 12 bolt POSI units in non-disk rears. The SD unit OTOH used 22 plates with spring pressures of 200 ft-lbs (vs the 50 ft-lbs for the fctory Posi). I had a phone conversation and some emails with Wayne a few years ago regarding those differences, but he told me he had little experience/knowledge of the SD package. I did send him some photos and measurements from the one I have at that time.