What way to repair stripped spline on snowblower auger?

[Manual Mac]

Spline joints benefit from grease, even if they don’t slide.
they rust & wear fast without it.
if any of you have had Airhead Beemers you know about separating the trans & engine an inch or so & with a small brush, lube the trans input spline every 20,000 miles or so. Failure to do this is expensive.
BMW calls this a spline lube.

 

[John O]

Spline joints benefit from grease, even if they don’t slide.
they rust & wear fast without it.
if any of you have had Airhead Beemers you know about separating the trans & engine an inch or so & with a small brush, lube the trans input spline every 20,000 miles or so. Failure to do this is expensive.
BMW calls this a spline lube.

It's not my blower. Looks like the original ujoint failed so they put a straight shaft with splines welded on the ends in place. Miss-alignment and lack of grease killed it.