Hey guys i'm new here so hello all

I got a problem with my sportsman. The rear left tire doesnt spin whether its in 2WD or AWD. I jacked the quad up and spun the rear left tire and its skipping the teeth and not doing anything. I pulled the CV out and the CV looks find but the splines inside the rear diff were stripped on that side. I went on bike bandit to try and find the part but the diagram is a little confusing. Does anyone know what part I need?
Thanks
I thought on the bikebandit site under 2005 sportsman->transmission->gearcase-> #19 looks like what I need but it doesnt mention if there is splines on itt