Did you deadhead the system before it cracked? Pumps don't really make pressure, they withstand pressure. When the system is at rest and oil is simply making a loop, there is little pressure in the system. Deadhead the system and you get a pressure spike right back to the outlet of the pump. That little squeal you here is the relief vavle opening and bleeding off excess pressure to stay with in system operating ranges. Too high of pressure is very hard on the pump. When you look at a worn gear pump, you see the wear is on the inlet side. That is because under high pressure, the gears defect back against the housing. The milky fluid and the thought the pump froze may have been a red herring. The relief vavle may off stuck close giving you extreme system pressure until the pump could no longer take it. I once had a T190 that needed a new pump. Installed and check relief, over 5,000 psi, spec is 3,300. That quickly explained the first pumps failure.
