Various embodiments include approaches for installing a flow sleeve relative to a gas turbine transition piece. Some embodiments include an apparatus for coupling a gas turbine transition piece with a flow sleeve, the installation apparatus having: a radially inner ring; a plurality of expander segments extending radially outward from the radially inner ring, the plurality of expander segments each having an axially ramped segment sized to gradually expand the flow sleeve to couple with the gas turbine transition piece as the flow sleeve is moved along the plurality of expander segments; and a circumferentially disposed space separating each pair of adjacent expander segments in the plurality of expander segments.