The Rangers staked starting pitcher Matt Garza to a 3-0 lead through four innings, but Los Angeles came up with six hits in the fourth and held on in the closing innings to hand the Rangers their second straight loss.
Mike Trout and Kole Calhoun both singled in a run in the big inning before Trumbo homered to left-center.
C.J. Wilson (15-6) benefited from the comeback to get the win, allowing four runs on seven hits in 6 2/3 innings. The loss was hung on Garza (9-4), who served up six runs on nine hits in seven innings.
Texas trailed by two heading into the ninth, but scored a run against closer Ernesto Frieri when Leonys Martin doubled with two away and scored on a single by Andrus.
Frieri then struck out Ian Kinsler to pick up his 31st save.