The past form of need to is needed to, while need as an auxiliaryA helping verb used with main verbs to express mood, voice and tense. E.g.: I can't stand when I am disturbed. ("can", "am") is used with perfectThe aspect expressing completion. E.g.: He’s finished university. infinitives only in negativeA declarative sentence indicating "no". E.g.: Tim has no friends. sentences to refer to past timeA concept which is related to our perception of reality; that part of existence which is measured in seconds, minutes, hours, days, weeks, etc.. Note the difference between didn't need to and needn't +perfect infinitive:

Geoffrey didn't need to buy milk as he had plenty at home. (= Geoffrey didn't have to buy milk... It wasn't necessary for him and probably he didn't)
Geoffrey needn't have bought milk as he had plenty at home. (it wouldn't have been necessary for him but he did)

The first sentence suggests that it was clear in the past that he didn't have to buy milk (he could have bought some nonetheless), while the second says that it turned out only later that it hadn't been necessary.

HAD TO
Modals expressing past necessity / obligation SHOULD + perfect infinitive