D2 5U injection pump

Doing the annual on this engine, I found the oil level in the pump/governor assembly very low, dangerously low. I hadn't noticed any severe leakage, mainly because the lower rocker cover gasket was leaking enough to pretty well oil everything. I had been topping it up every couple weeks or so and not using that much oil per add.

Question: Oil seal, part #4B4865--Does it seal engine oil out of the injection pump, or pump oil out of the diesel oil system, or both? If this seal failed, where would the oil go? Is there some place else that would leak oil out of the governor and/or pump? I can't see any obvious leak points.

The engine was shut down in June, drained hot. That's when I found the low level and examined it for leaks. I plan to start up again in about October, am doing the mundane dirty-hand stuff now so it will run through a winter again without any problem.

As always, help offered here is greatly appreciated and I thank you,

Jack

4B4865 is replaced by 1H5959.
The seal lip faces towards the pump so is meant to keep oil in the injection pump. Any leakage winds up in the engine main sump through the same route that dumps fuel into the crankcase when the fuel gallery seal between the filter tower and the injection pump housing leaks.

Thanks, O.M. I suspect that's the answer. I'll dig out my long socket extensions.