With the score tied 2-2, Trout led off the sixth with a long blast to left field off Athletics starter Tommy Milone that landed well up into the second deck. One out later, Trumbo sent a liner over the left-field scoreboard that was initially ruled a double, but changed to a home run after a video review.
Albert Pujols added a sacrifice fly in the eighth that provided the eventual game-winning run. Kendrick finished 3-for-4 with a bases-empty blast in the second for the Angels, who avoided a three-game sweep.
C.J. Wilson (3-0) overcame five walks to notch the victory, yielding two runs on six hits while striking out five over 6 1/3 innings.
Ernesto Frieri came on to record a five-out save, his fourth of the season, after the Los Angeles bullpen coughed up two late runs.
Milone (3-3) fanned 10 but was touched for four runs on seven hits over seven frames.
Adam Rosales went 3-for-4 with an RBI while Josh Donaldson, Nate Freiman and Luke Montz each drove in a run for the A's.