I think past experience definitely plays a huge formative role. I also wonder if both the trust and fear aren't about the T at all, but rather (dis)trust and fear of oneself? There's a deep desire, perhaps, to have the T accept and hold that (dis)trust and fear, and so neutralize them, but no developmental experience of being successful doing so.

I never felt distrust or fear of my T, but I certainly experienced those feelings about myself. The way I got past it, or healed it, was exactly by allowing my T to take those feelings on, hold them, neutralize them, and by doing so, allow me to borrow his strength until I could feel powerful enough myself. I could have the developmental experiences I'd missed in childhood. But the fear was more a feeling of "what if I can't follow through? If I fail despite T's competence and empathy, what else is there?"