Jon,
What model is your 85 Tag? My 506 was built in March of 85, meaning it just celebrated its 37th "buildday." I don't think the Pitman trans were discontinued until 88 or 89, so anything before that is the best I'd say. They have such a smooth and relaxing sound compared to the loud one of the orbital. Not to mention, I think the helical agitators are much easier on the eyes as well, than the orbital ones.
20 years seems pretty short compared to how long many Luxes have lasted! My oldest one (Model L) is 50+. Sadly, I can't say my newest (Ambassador) is built to last the same way is its earlier, metal cousins. Those motors were notorious for failure I think.
I'm so sad to learn that both Lux and Whirlpool/Maytag are discontinuing parts for these wonderful, quality machines! They are definitely NOT built to last anymore, and the only thing that seems to matter now is people buying new ones often for the money.
Even the late 90s/early 00s Dependable Care 'Tags weren't quite the real thing, I'd say. I think when the square panel went away, that marked the end of the quality.
Jack