Went back for a visit today,they now believe it is a bad driveshaft(the 4 foot long telescoping shaft from the mid-pto to the front). The shaft on the unit had quite a bit of run-out they said. They have a shaft on order to try now,seems most likely the cause. Thanks to all that responded,I will update later on with results.
I know this is an pold thread but after one "very light usage" winter I found that my 47" blower is making a lot of noise.. when disconnected and turned by hand it sounded like a bad bearing on the end of the pin where the small sprocket is located.. JD replaced bearing and spent 9 hours on it but was unable to determine where what was causing noise.. Any update on how this worked out for you? Any future problems..