A gearbox mounting link between a gas turbine engine structure and a gearbox mounting location comprises an engine attachment piece rotatably secured to the gas turbine engine structure. The engine attachment piece comprises first and second plates extending in parallel planes and separated by a gap having a gap width. A gearbox attachment piece is situated between the parallel plates, and is secured to the gearbox. A breakable primary retention fastener extends snugly through the parallel plates and the gearbox attachment piece, thereby rigidly retaining the gearbox with respect to the gas turbine engine in two degrees of freedom so long as the breakable primary retention fastener remains intact. A durable secondary retention fastener extending snugly through the parallel plates, and extends with clearance through the gearbox attachment piece via an oversized fastener passage, thereby constraining the gearbox attachment piece in the event that the breakable primary retention fastener breaks.