Thank you, Leonz, for your valuable input. So far I haven't seen any availability information on a metal impeller blade . . . ( the $$$ for a direct JD fiberglass replacement is $ 144 !! )
At best, this 54" snoblower is Mickey-Mouse in it's design . . particularly given all the u-joints between the mid-ship, belly PTO; ie, there's one at the PTO , there is another one at the opposite end of the drive shaft where the thing is ' supported ' by twin bearings at the front of the tractor, there's another one between the PTO shaft and the drive shaft of the blower, and another one connecting that shaft to the chain sprocket drive on the blower! You can try and lube each u-joint but they are hard to reach, particularly in the snow!
Whoever assembled my rig ( which I bought new at the local JD dealer ) apparently failed to properly torque the PTO front support bearings and midway thru the second winter, that whole assembly was well on it's way to self destruct. Of course, being out of warranty, a new PTO shaft and front bearing assembly were considerably pricey + installation. Last winter we never had a snow that was deep enough or ' dry ' enough to use the blower. So I bought a 54" front plow blade as a backup. It took me most of the season to finally get the ' angling adapter kit ' hydraulic line installed where it wouldn't leak fluid. ( more Mickey-Mouse )
So here I am about midway thru a moderate snowy winter . . . and the drive shaft is beginning to make ominous rattling noises . . . like maybe those front support bearings are self destructing again?
Aside from the wear on the impeller, one of the things that will cause a clog is the buildup of snow at the base of the chute where it connects to the top of the blower housing. If the chute is aimed at either extreme left or right, the snow will build up on top of the blower housing to the point that the accumulation will clog the chute. It's a nuisance to get off the tractor and clear that snow away every couple hundred feet.
I bought some spray stuff which supposedly ' lubricates ' the impeller and chute, but it makes little difference.
As a final alternative I have had a rear scraper blade to plow with . . but riding side-saddle, contorting my body, and twisting my neck is a real drag!
I replaced the original scraper blade with a Land Pride 1560 which accepts skid shoes! I'm never going back !