New Holland 56 Rake

Tried searching for an answer but cannot find anything....

 

Dad tried raking over some windrows the other day and said that the rake was making a rattling sound when the bars were turning, however when he dug into a windrow it stopped turning.   I have opened up the gear box and it is still well greased and I see no issues with worn gears etc.  I jacked up the drive wheels and the outside wheel will turn the rake, the question I have is, the tire that is attached to the shaft to the gear box "free spins" with no resistance.  Is that normal or should both tires actually drive the rake?  I see that there is a "hub" on that wheel but there is no clicking noise when I turn it.  Any help would be great.

 

 

~Ben

New Holland 56 Rake