A mounting system is provided to couple an engine unit including a turbine engine portion coupled to a gearbox portion about an axial axis to a support structure. An aft mounting device can couple the turbine engine portion to the support structure. A force determinator can be configured to determine a force load of the engine unit at the location of the aft mounting device. The length of the aft mounting device is adjustable between the turbine engine portion and the support structure in a radial direction to substantially align the gearbox portion and the engine portion relative to the axial axis. The aft mounting device may be sized to a desired length to correspond to a force load of the engine unit during the running condition.