well.... you guys seem to be right about the belt. I thought for sure it was tight, but I got it a little bit tighter & no problems. My dealer has told me this was not an uncommon problem.
Dealer has a different belt (green side or line??) that I am supposed to pick up. apparently this style of belt has a steel cord or braided steel in it that will prevent it from stretching / slipping.
Since the last snug of the belt seems to have solved my problem I haven't been in a hurry to stop by & pick up the belt. But will try it out since the dealer is very curious to see if it helps.
just had the 50 hr done @ dealer (actually had 69 hours), everything checked out great.
The DK45 is one heck of a machine!
Now looking for a ZTR mower (Husqvarna maybe)... it just doesn't end......