ATF. I have a CP 834 (no, not a 734) that I bought in 1973. It was the cheaper version of the 734 and I have no idea how many diesel engines I tore down with it. When I hit something tight-tight I gave it a drink and the ATF came out brown. I wiped it off and kept going.
48 years later, it still works and the only repair I did was replacing the nose ring that retains the socket.
48 years later, it still works and the only repair I did was replacing the nose ring that retains the socket.