I'm new to this site. I have a 1990 5.9 12V engine in a 1-ton 4x4 p/u. The power steering pump seems to have locked up. I pulled the power steering / vacuum pump assembly. The drive gear (on the power steering / vacuum pumps assembly) has some of the teeth badly damaged. I purchased a newer (1998?) power steering / vacuum pump / drive gear assembly. I noticed that the drive gear on the newer assembly had a different number of teeth than the old gear. I would really appreciate any advice on what year parts will work together. I am also of the understanding that I will likely need to pull the camshaft. Thanks in advance.