if you have the stripped shaft and sprocket, post a pic of them. Without seeing it, my guess is a machine shop could remove the stripped splines and then pin/weld a bushing with external splines where the old splines used to be. Same on the sprocket- drill/lathe out the stripped splines and insert a bushing with internal splines that mate up to your newly splined shaft. There's probably a number of ways for a machine shop to make this work...just need the right idea and right machine shop.
Dad and I owned had a decent machine shop until it burned down. At one time I could have cast new sprockets - I had a 75KW Inductotherm coreless induction furnace. Now just scrap. I've already scrapped 50 tons of just metal working machinery with more to go. The scrap yard got pissed when I put 82K/lbs of lathes, mills, and drills in a 70yd roll off last year. I need the excavator now - not a month or 2 down the road. Now! My village is being a bunch of bullies and kicking me while I'm down.
I've found messages that said DANA made these drives. They used undersize parts in these drives. Not surprising being an passenger automotive supplier. There simply isn't much material to work with and I can't take the machine out of service for weeks to muddle through repairing it.
If I could actually push the shaft out of the drive without disassembling the drive like I was told by Crawler Parts in Indiana - I'd be willing to put a new shaft in it for the $450 I can buy one for. I don't feel there would be sufficient wall thickness of an externally splined busing to attempt a repair the shaft. A failed repair would mean days of work. To attempt to save the sprocket I have. I would have to send the new shaft off to have someone make a bushing with internal 29 tooth spline to match the shaft. Bore a lot of valuable strength out of a wimpy sprocket so it can have the internally splined bushing pressed into it. Then weld the bushing in place. Depending on how it is welded - machining could be required of the welds. All along hoping that the thinned sprocket hub doesn't break later.
Crawler Parts said just weld the sprocket to the shaft and pay the piper later if the inner pillow block bearing fails. I'm not sure how they would weld it - through holes drilled through the sprocket hub to the shaft spline? The pillow block bearings bear against each side of the sprocket so welds can't effect the sides of the sprocket.
Here is a picture of how little difference there is between the shaft's spline and the bearing journal.