Specifically methylates the adenine in position 37 of tRNA(1)(Val) (anticodon cmo5UAC). adenosine(37) in tRNA1(Val) + S-adenosyl-L-methionine = H(+) + N(6)-methyladenosine(37) in tRNA1(Val) + S-adenosyl-L-homocysteine Belongs to the methyltransferase superfamily. tRNA (adenine-N(6)-)-methyltransferase family.