86 Golf,Halfshaft. Wheres the big washer go.

I started to change my left driveshaft on my 86 today. After I had the driveshaft out of the hub hanging down, still attached to the trans, for about 5 minutes, A big cad plated washer fell out on the ground from somewhere. Its big enough to fit over the driveshaft end, and against the wheel bearing, and fits inside the seal too.It has grease on it. But I changed the wheel bearing and half shaft before and dont remember it being there. Also there's a shiny spot with a groove worn. where it looks like it fit against the wheel bearing, but it looks like it was spinning. My axle nut was very tight. So I fit it together and the axle nut doesnt pull down enough, like it wasn't there before or now the bearings positioned wrong. But it does fit there real nice. I don't know where else it could go. but it looks like it was there, but not really. There isnt one on the other side either. Now I wonder if an alignment shop did it, to fix the axle shaft end stop problem, after I put new struts on, but they'd have to be really into VWs to know about that. But my axle nut doesn,t pull down to the same spot when I took it off. Anyhow I stopped work, because of this, now its snowing. So it can sit and rot until I get around to it again. Any ideas.. Thanks Vern Diesel