I have a mini-zoom, 1540 zrt that I have been real happy with. It was purchased in 2009. Recently it started bucking and jerking, it was unsafe to ride it. I checked the belts, put new dampers on it - same results. Finally I was allowed to talk to a factory rep (don't get me started on them not allowing us to call in normally) and he said, I hope this isn;t it but check the frame! It ends up on many of their zrt's (not sure how many models) they have a known problem of the frames breaking right in front of the flange holding the hydros. Sure enough one side was completely broken, the other cracked. Ariens knows all about this problem, they SELL frame repair kits for many models.
My mower problem was the broken frame allowed the hydro to move a little bit, causing the jerking.
My mower problem was the broken frame allowed the hydro to move a little bit, causing the jerking.