Is it the actual sight, sound, smell, taste, tactile sensation, idea, or the feeling based on them.
At Savatthi. There the Blessed One said, "Monks, there are these five clinging-aggregates. Which five? Form as a clinging-aggregate, feeling as a clinging-aggregate, perception as a clinging-aggregate, fabrications as a clinging-aggregate, consciousness as an a clinging-aggregate.
"And what is feeling? These six classes of feeling — feeling born of eye-contact, feeling born of ear-contact, feeling born of nose-contact, feeling born of tongue-contact, feeling born of body-contact, feeling born of intellect-contact: this is called feeling."
-- SN 22.56
"There are, O monks, these three feelings: pleasant feelings, painful feelings, and neither-painful-nor-pleasant feelings."
-- SN 36.1
"Whatever feeling is past, future, or present; internal or external; blatant or subtle; common or sublime; far or near: That is called the feeling aggregate."
-- SN 22.48
The aggregate itself is not the clinging to it. upādānakkhanda means "clung-to aggregate", not "aggregate of clinging". Otherwise, it would mean that upādāna was the truth of suffering, when in fact it is the truth of the cause of suffering (i.e. tanha).
So, vedanupādānakkhandha means the aggregate of of any and all feelings, when clung to.