I have "Hudson's" too, but never many, as they're on various grafts high on old trees. But I think they're still hanging on... Though I found and pasted the following, your tree may simply have 'run out of juice' and can't ripen such a heavy crop; I wouldn't be worried. Had this happened on a regular, or poor set year - then I'd worry. Here's what I found online:

"Premature fruit drop is often related to unfavourable environmental conditions, such as late frosts, excessive heat or cold, and abrupt changes in humidity. Symptoms may be soil related, resulting from irregular watering and improper nutrition. Nutrient deficiency is a common problem. Boron-deficient green peppers, for example, will even exhibit a certain amount of fruit drop. Although there are characteristic deficiency symptoms associated with each nutrient, plant expression may vary between species. Deficiency diagnosis is further complicated if more than one nutrient is deficient in the soil. In Manitoba, only nitrogen, phosphorus, potassium and sulphur are of particular concern with respect to fruit production. Herbicide drift may also lead to premature fruit drop."

"Pathological or pest-related fruit drop is more likely to occur late in the growing season when the fruit is nearing maturity. Common insects that cause premature fruit drop include apple maggot and plum curculio. Common diseases include apple scab and peach leaf curl. Insects and diseases tend to have more visually identifiable symptoms and are, therefore, easier to diagnose than environmental or physiological disorders."

From: http://www.umanitoba.ca/afs/hort_inquir ... _drop.html