In our study, we aim to identify the functional role of specific phonon modes in driving or suppressing exciton transport in pentacene, a prototypical organic semiconductor. After photoexcitation, pentacene undergoes singlet fission via a charge-transfer intermediate state, which leads to the formation of triplet excitons. A correlated triplet pair formed during singlet fission can fuse back into a singlet, it can dissociate and diffuse, or undergo triplet annihilation back to a singlet exciton, and it can be difficult to distinguish between these two states in the resulting exciton transport dynamics. Triplets have slower diffusion rates, but longer lifetimes and are capable of travelling several microns. Maximizing this long range triplet exciton transport is crucial for implementing singlet fission materials widely in photovoltaic devices. One avenue to maximize long range transport is to identify crystal lattice vibrations that drive favorable transport dynamics to inform the rational design of new materials for use in photovoltaic devices.