Recently looked into this as I was R&Ring my power steering pump. Dealer wants WAY too much for a new one, and didn't indicate that there was a rebuild kit available. Spoke with local Cummins shop, they said the pump was a Dodge item, but the parts guy said he had a contact that could probably rebuild it. I took my chances and put the old vacuum pump back on. I did, however, replace the shaft seal between the vac and ps pump. Pulled the seal, took it to local bearing house, and they matched it for about $3. So far, so good. No oil leaks.
Pat