Ps pump bolts to vacuum pump, which is bolted to the back of the timing cover and runs off pump gear. There's two teeth on the ps which your obviously familiar with, the Vaccum pump has the same set up and they meet in the adapter housing. The two teeth on the vacuum pump have been know to sheer off as stated above. I would look up Gould gear and give him a call. One on the most helpful and knowledgable people I have spoken to about our trucks. Good luck, if you end up needing a vacuum pump pm me