Spaceman

Yes you can use lithium grease for everything on your snowblower.  Lithium grease has a high heat tolerance and is also good at displacing moisture.  It adheres well to metals and helps stop corrosion.

Does anyone have any experience with tire chains on their snowthrower?  I find my wheels start to slip when I run them over packed snow, would tire chains help ?

I bought a 928E from Lowe's in Hamilton Canada in November.  I was told by the salesperson that John Deere does not allow retailers to assemble the units.  They're all assembled at the John Deere dealership in Smithville.
I was told at the John Deere dealership that the engine is rated between 9 - 10 H.P.  They are no longer allowed to rate their units in H.P. because of law suits in the U.S.  It appears people have launched law suits over manufacturer's "rated horsepower".
I was told by a salesman at John Deere that the units are made in Illinois by B&S to John Deere specifications.  John Deere stopped making snowthrowers a few years ago after several winters of low snowfall.  They didn't sell enough units to justify an assembly line.
If you have problems, take your snowthrower directly to a John Deere facility.  I had trouble removing a broken shear pin.  The mechanic showed me a trick, and gave me some useful info about the machine.  I was treated very well there.