I seriously doubt that not putting oil in the bowl for your last four trips seized the pump to point of locking up.
Usually what happens is, no oil is put in the bowl... EVER! Rather than locking up, the shaft and bowl bushings wear badly, until the the bushings wear completely away, followed by the bore in the bowl being destroyed. Four trips is not going to cause catastrophic failure.
On the other hand, the thrust bearing really should get a lot more attention than it does. As the name implies, the thrust bearing manages the axial (fore/aft) movement of the shaft.
Ponder this for a moment. In a pump with an A impeller producing 150 PSI of bowl pressure, the shaft has over 9,542 pounds of force pushing forward.
You actually want to over-grease the thrust bearing. The idea is to flush moisture out of the bearing. Yes, you will have to clean up some grease that is forced out around the driveline yoke. We recommend ten pumps of grease into the thrust bearing every other trip.
A common issue is when operators allow the water level, in their bilge, to rise to the level of the thrust bearing. The bearing gets pretty warm during operation, when the water level covers the bearing, it cools rapidly, the grease and bearing contracts, causing a low pressure, and moisture finds it way in to corrode the bearing. Once the bearing experiences a little corrosion damage, it starts to self destruct.
How can this be prevented? If you know that you got water in the thrust bearing, flush it out with grease at the end of the day. In an insert pump, don't let it go until the pump self distructs, they are very expensive to replace the suction housing.
More importantly, once the thrust bearing fails, the only thing controlling the thrust forces is the engine thrust bearing.
The thrust main bearing is not intended to control much load. When the crankshaft is pushed forward, the crankshaft thrust surface is forced against the bearing surface. These mating surfaces rely on oil leakage from the main journal diameter. The oil takes the path of least resistance, which is to the front of the thrust main bearing. The result is hard metal-to-metal contact that sends debris through the engine, destroying everything.
Here are the first things I would do: 1.) Check your oil for metal particles. 2.) Put a breaker bar on your harmonic damper bolt and see if the engine will budge. 3.) Check the condition of your battery, cables, starter, etc.
Should you then want to remove your driveline, you have a two-piece driveline. There are four nuts and bolts in the middle, holding the two halves together. There are also the previously mentioned bolts holding the front half of the driveline to the PTO or crankshaft. Lastly, there are the two u-joint cap u-bolts on the pump shaft yoke. Be very careful to not drop a u-joint cap and loose the needle bearings.
Hopefully your thrust bearing didn't fail, destroying your engine. If so, your impeller will have cut into the suction. It could be pricey.
Good luck
