Perhaps Magic Clean can clarify, but unless I'm wrong, LB5500XL (1982 model) was the first Whirlpool-branded DD. I participated in delivery/setup of several while working for the local Whirlpool dealer. It was (or is, as some still may be in existence) 24" wide, tagged as Design 2000, and did not have neutral drain. The lint filter is the passive under-basket type. Four water levels. Cold/Cold, Warm/Cold, Hot/Cold. Regular/Heavy, Knits/Gentle, Perm Press, Soak/Pre-Wash. Bleach dispenser. No softener dispenser, although the agitator has drain openings to allow for it. No clothes guard ring on the basket. Agitator as pictured. Plastic insert lid handle.
The LA7400XM (1984) Design 2000 my grandmother had was pretty much the same, except had the clothes guard ring. Still was spin-drain.
I have Service Manual L-46 "Design 2000 Direct Drive Washer" dated 1981. Agitation is stated as 100° arc, 177 to 181 SPM high speed (vs. 195° arc @ 68 SPM for belt-drive), 118 to 122 SPM low speed. Spin is 640 to 650 RPM high (vs. 500 RPM for belt-drive), 425 to 429 low.
I also have Service Manual L-55 "Direct Drive Washers" dated 1987, which covers the neutral drain design. Can't say if 1987 is an indication of when neutral drain went into effect, or if that's just the printing date of the service manual. Parts diagrams show examples of both a dual-action agitator and a straight-vane with removable filter barrel. It was never clear to me why neutral-drain was added, perhaps Leslie can address that as well. Maybe one reason was to eliminate the high-speed spin/drain leading into slow spin, consumers who noticed that may have complained. Granny ran her machine for 15 years with no repairs, not even a drive coupler.
