The main aluminum gearcase on the rear that the electric motor bolts to actually broke in half. I found the replacement part number from Hisun University Manual. I ordered a replacement gearbox from a dealer in Kansas, IIRC (they were the easiest to actually source it from and talk to. I think it cost about $1100). I thought the process to replace it would be horrifying but it was actually fairly straightforward. A reasonable mechanic should be able to complete it in one day. the rear axles/tires/suspension DO NOT have to be removed in order to accomplish the task (but the splines are retained by small retaining springs to they wont just pull out you have to "shock them out" with a screwdriver/wedge/tap with a hammer operation). everything else just unplugs and unbolts , reverse the process and you're finished. keep the phase order correct to the motor (it is 3 phase ac induction type motor). there is an encoder (for speed feedback) and a thermistor on the back of the motor you have to unplug. I thought it would be worse than it was and you can do it single handedly. just thought I would share for anyone going through the same process.