18542? I have the same mower, same age, with about the same use case. Zero issues to report.My 5-year-old Husqvarna has a plastic CVT transmission made by General Transmission. I have a very gentle but long hill in my front yard, I mow less than an acre every 2 weeks for about 5 months out of the year, my mower has 88 hours on it. The belt used by the CVT was first replaced at 14 hours for "overheating" - the mower just stopped moving and there was a burning smell. The belt has since been replaced twice more for "overheating". The belts used by the CVT are not covered under warranty because they are considered a normal wear item. These transmission are huge hunks of ****.
It sounds like you may have an issue with your variatior or something causing excessive belt slip. Do you mow thick grass or brush?