Looks to have a K241AS (10HP) engine.
Serial number plate is located here in this photo. Report back with numbers and we can tell you what it is or was.
Yes, they are rated at 3.3 Ohms. Made in Mexico for the North American market. Oil filled.
https://www.rockauto.com/en/moreinfo.php?pk=5472996&cc=0&pt=7060&jsn=3
Is it 15 spline? Is this what you want?
https://fortwayneclutch.com/product/6-series-l600-series-1-x-15-spline-short-couple-yokeshaft-sku-106-0615/
https://www.ruralking.com/weasler-6-series-yoke-with-1-15-spline-spindle-bore-and-spindle-connection-106-0615
Danuser Machine Company built the post hole diggers.
Danuser Machine Works built the loaders.
I have read they were not affiliated but don't know for sure. Maybe you can find out at the garden show.
I can't even find the 56v battery in the parts lookup. The 56v charger is 519.64 thru Cub Cadet.
The 48v battery was 1,400.38 but currently not available.
https://www.cubcadet.com/en_US/batteries/charger---56v-li-660w/725-18084.html...