Freehub disengages and then rengages — what is the issue? I have a Hope Pro hub and shimano freehub body with 11 speed cassette on my MTB. Recently when pedalling on occasion the resistance in the pedals disappears (like the chain has come off). It seems as through the freehub has disengaged. When I stop the freehub and pedals re-engage and I can continue for another few miles or so. It has only started happening recently ... never had this before. 

Any idea what is happening. Do I need a new freehub body or do you reckon a service will do the trick? 



Thanks all.  I'll take the freehub off and take a look.

The thing that is odd (to me) is that I'll be pedalling and suddenly it will freewheel. There is no sound -- it is like the pawls suddenly retract ... i would have thought when pedalling it would have been hard / impossible to retract?
Most likely pawls or other parts of freehub's engagement mechanism have become sticky. Opening it, cleaning it up and applying light grease (if at all) should help.

Much less likely but not impossible is that the pawls have become worn. Replacing them is then in order. In any case, servicing the freehub is the first thing to do.