TwinTub TL stacked sets continued using the DD mechanism for several years longer than full-size TLs. May have been still used up to 2017. WETLV27F (2016) is DD. WETLV27H (2018) is VMW.
Whirlpool's earliest DD 24" model I believe is LB5500XKW0 (1982). I have a printed service manual L-46 (copyright 1981) with that reference, and that's the model we sold at the WP dealer where I worked at the time. But IIRC from previous mentions by John Lefever, the earliest 24" DD production/serial dated to 1981, probably as Kenmore. Sears offered them a little earlier than WP. The initial design had the transmission turned with the motor/pump oriented toward the right/rear corner instead of at the front.
A service manual I have for VMW references 2010 for "year of introduction" and "year of production" for model and serial syntax (41st week for "week of production"), if that means anything.
