Rutnick

Anyone have a tech manual with specs for the rear wheel? I replaced my bearings the other day and now when I coast above say 23mph in gears 5-10 in the rear I get this dang walrus sounding noise and my chain goes slack. It only does it when I coast. Any ideas? bad cassette body bearing? Something wrong in the pawls? Honestly, the design of the whole thing is really so simple that it has to be something very easy. When I does make the noise, I can pedal a few revolutions, stop and it will go away.