My friend put a rearend in his 85 1/2 ton P/U. The truck had a 2.73 geared 10bolt. He put in a 3.42 geared 12 bolt out of a 79 Jimmy. He just sent me an email and said that the ujoint yoke size is different and his ujoint wont work? I was under the impression that all 1/2 ton GM ujoints were the same? Appearantly not... Will the yoke off his old 10bolt work on that 12bolt to get the ujoint size back to what it was?