I have a Kenmore 90 series washer that works completely fine except for this thumping noise heard as the machine winds down from it's spin cycle. I found a post that instructed to use a little high temp silicone on the inside of the brake drum. I have tried this and it didn't make any difference. I have also checked the skateboards as s\described in here and they seem to be aligned (I could push lock pins into the holes).
Any advice on what to check next?

I've just noted that if I open to door while in spin the knocking starts as the agitator speed and drum speed start to vary. The agitator stops quickly and then then knocking occurs as the drum slows down

Thanks for the reply, I've done as you said and there is not really any clunking noise, you hear it slightly just as it starts to turn the basket but it feels smooth and spins basket no problem. I ran it without the cover on and when the spin cylce ends the shaft seems to stop quickly and smoothly and I don't feel any clunking in the tranny casing. the noise seems to be more from the basket area?

You might have a bad drive block that the tub sits on, also check the bottom of the spin basket. Sometimes the filter breaks and scrapes the bottom of the tub.