here you go, but it doesnt look like a separate part so youcan only get it as part of buying the whole tranny
https://www.partstree.com/models/yta-22v46-960450051-00-husqvarna-46-yard-tractor-2015-07/drive-2/
you have only 2 choices left, buy a new tranny, or buy a parts mower and take that tranny, or the parts you need from it, off to fix yours
then maybe there is still a 3rd option is someone on ebay might be selling that part you need used
and in the future remember your lawnmower transmission is weak as **** and not designed to pull anything around more the a small lawn cart with 25 lbs load in it