Green’s Dictionary of Slang

1. a cart (e.g. as used in a hanging).

1788		‘De Night Before Larry Was Stretch’d’ Irish Songster 6: When he came to the nubbing chit, / He was tuck’d up so nate and so pritty, / De rumbler shov’d off from his feet.
c.1816		‘The Night Before Larry Was Stretched’ in Farmer Musa Pedestris (1896) 81: The rumbler jugg’d off from his feet, / And he died with his face to the city.

2. a hackney carriage.

1821

W.T. Moncrieff Tom and Jerry I vii: A rattler is a rumbler, otherwise a jarvy! better known perhaps by the name of a hack.

3. a four-wheeled cab; thus rumbler’s flunkey, a footman who runs for cabs in return for tips.

1828		‘The Song of the Young Prig’ in C. Hindley James Catnach (1878) 171: Turned rumbler’s flunky for my meat, / So was brought up to the halter.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.