A gas turbine engine has a fan and a turbine section including a turbine rotor to drive the fan through a gear reduction module. An input shaft downstream of the turbine rotor includes a flexible mount driving the gear reduction. The input shaft is mounted within a bearing module. The gear reduction module has static structure mounted to an engine housing through a flexible mount. Oil is supplied into the gear reduction. An oil tube supplies oil from the gear reduction to the bearing module, and is received within openings in the static structure, and a housing for the bearing module. The oil tube extends through an assembly guide having a guide opening spaced away from an outer periphery of the oil tube. The guide opening is intermediate the openings. A method is also disclosed.