if you go with the Hyperglide freehub then you need a 6 speed cassette, they don't make a 5 speed for this. they go from 6 - 10 gears , it is nice to keep it original when all possible in my book .it is normal for a wheel when it stop spinning for it to stop with the valve at the bottom. try flushing out with WD-40 and spin the body when you do and after it dry then try oiling it again .