Hi BlueL82, sorry I didn't see your post earlier, but if you still have questions about preload here is my 2 cents. I assume you are talking about pinion bearing preload. If you check the websites of diff retailers i.e. yukon, etc, they typically have setup specifications. Remember to use the D44 Corvette specific numbers. 14-19 in lbs is correct for new bearings. used bearings are typically about 50% of new, in this case Yukon lists 6-9 in lbs for used bearings. This is important because the new bearings will wear in relatively quickly and then remain fairly stable for the life of the bearing. So new bearings, use the new specs, used bearings, use the used specs. You do not want too much preload on bearings that are already worn in. remember also, new seals will typically add 1 in lbs each. The seals will wear in also and the total preload will correspondingly drop slightly after wear in. It is a big job to do so new bearings are always recommended, but you be the judge of how many miles you plan to be driving and whether you ever plan to do this job again.