Hey thanks alot man I appreciate the advice and it looks that you are right. We pulled the half-shafts out and they were fine on both hub and differential ends. Pulled tranny off and clutch and pressure plate were fine also. The input shaft spun freely with no unusual noise and it did not lock up. So we put the half-shafts back in the diff and spun them and it kept on locking up, so it looks like something is wrong in the diff. Thanks