IMPORTANT NOTE: DOWN, UP
It’s important to note that the Spicer Parts calculator refers to the slope of a component in terms of where its rear sits relative to its front. If the rear is lower than the front, the item is on a down slope. The opposite means an up slope. Why this is so important to note is with regards to diff-pinion angles. The pinion angle is almost always on an upwards slant, but, for the purposes of this calculator, it must be measured as a down slope, as the rear sits lower than the front.