It's a matter of combining it with "for more than two years". had been (in the state of being) gone (= away) (for a period of time) — makes sense . had gone (= left = went away) ( for a period of time ) — doesn't make sense because it's a single act that can't last for more than a few seconds.
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Amir OghlowIt doesn't make much sense to say "I had gone for a period of time."I have to say "I had been gone for a period of time."Right.
Amir OghlowI had gone to Canada when I was young.OK. Or just I went to Canada when I was young.