Gearbox rhymes with:
tarbox, boombox, breadbox, fischbach's, icebox, jukebox, mailbox, matchbox, saltbox, sandbox, skybox, soapbox, tarbox, tinderbox
Gearbox sounds like:
garbacz, garbage, garp's, garps, gearboxes, geographic, geographic's, gerbasi, gerbig, gervais, gervase, gervasi, gervasio, giraffes, graboski, grabowski, grabs, grabski, graffius, grapage, grapes, graphic, graphics, graphics', graphs, graves, graves's, gravies, gravois, grbavica, greaves, grieves, grievous, griffey's, griffis, gripes, grips, grivas, grooves, groppy's, group's, groupies, groups, groups', grove's, groves, grubaugh, grubbs, grubs, gurevich