I noticed a bit of a clunk when coming back on to the pedals after coasting the other day. This is a bike I haven't ridden much since I built it, but I don't remember it from when I fitted the cassette. I've taken it all apart and nothing looks damaged, and all parts are present.
Gripping the cassette, I can wobble it. There's only a very slight wobble on the free hub when the cassette is removed, and no discernible play if I wobble the wheel while in the frame.
Cassette is a CS-M8000 11 speed Deore XT, on a FH-M8010 rear hub. Both mountain bike parts, so no spacer required like it would with a road hub, but it feels like I need another spacer in there.
Anything else I should check? Or, if I go down the additional spacer route, what do I need?