Green’s Dictionary of Slang

(US Und.) sexually aberrant.

1935		A.J. Pollock Und. Speaks 44/2: Geared, sexually perverted.
1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1963		J. Blake letter 17 Feb. in Joint (1972) 202: He was geared and I just don’t groove sackwise with another geared one, no chemistry.
1965		Guild Dict. Homosexual Terms 18: geared (adj.): ‘Sexually perverted,’ according to Pollock. (Criminal slang).