Ihave a dodge caravan to start moving you hear afunny grinding noise then aftter about going 20mph it goes away what can be done about it

What year is it?? Is it a 4 speed?? This could be several things from a wheel bearing, CV joint, or even a differential pin walking out and cutting into the case (Very common in the 604 transmissions)

Give us some more info on the vehicle: Year, engine size and 3 or 4 speed would help greatly…