I have a Ariens 824 blower that's at least 15 years old.
Lately, I've been having trouble with the drive to the wheels...
When the machine hits resistance (like a snow bank), the wheels stop turning
(rather than spinning).

This happened a year ago and it was serviced locally, with a report of
"adjusted drive, no parts replaced".

I would like to avoid another $100 service charge and especially more
down-time, and don't want this to become an annual service event.

Any idea what was "adjusted"?
Should some parts have been replaced, since this "repair" was so temporary?

Thanks-

Karl