A transport lock assembly for the mower deck of a lawn mower automatically engages when the deck is lifted to a clearance height. The transport lock assembly includes a transport lock that is biased into a locking position by a biasing member. The transport lock engages a surface of a deck prop that is also used in the lawn mowers height-of-cut assembly. The transport lock assembly includes a transport lock actuator that is used to disengage the transport lock, and also includes a transport lock disabling mechanism that prevents the transport lock from automatically engaging.
