Can I replace the rear pinion seal on a 12 bolt with out taking the pinion gear out? I'm asking because I'm not having much luck finding the u-joint to hook the 79 12 bolt yoke to my 86 drive shaft. I am thinking of just using my 10 bolt yoke on the 12 bolt. The yoke on the 12 bolt seems just a tad smaller than the 10 bolt, but I cant really tell, the u-joint for the 10 bolt seems to pretty much fit it. Is it possible that they are the same size and I dont even need to do this? Any help??