I had a differential from a 46 Chevy half ton that was seized solid from sitting in water. A couple of months ago I submerged it in my farm dugout and just last week I retrieved it and was able to salvage the axles and crown and pinion. Small diameter bolts that would have twisted off came off easily, I was able to remove the bolt and drive the pin that holds the spider gears together out with little effort. I only want to use these parts for spares as the ones in the truck I am restoring are good. I have used this method on tools that are seized as well. It isn't a quick fix as I usually leave them in water for a couple months but it does work.