Spoke at length with Adem from True Travel
RCV is having Covid issues, axles have been back ordered since June!!
True Travel is aware of this issue and offered to send another axle BUT it might take MONTHS
So the other option is to clean up the splines ourselves to make it fit, which is what I will be doing (and others, we are not the only ones to experience this with RCV axles apparently)
This is a machining issue, the splines were cut deep enough but never "cleaned up" fully as far as I can tell.
If we look closely at the RCV vs the stock shaft you can see the machine marks on the RCV splines, look like a round bit cutting a square edge.
I used a file to clean up the leading edge so it is more "rounded" like the factory piece, and to remove some rough bits that were left on the edge (would catch my fingernail) and now I have the shaft very very close to sliding into the diff, but I am not going to force it.
Today I plan to clean up the valley of the splines very carefully with a Dremel until the shaft slides into place.
I will get some pictures of the process, I need to pick up some dremel bits in town this AM then it is on.
I assured Adem I could handle these mods no problem, I am used to this kind of thing doing custom fabrication.
I see this as a small hurdle and will overcome.
@JoleneTheExploder if you need you can send me your axle shaft and I can fix it up for you? Or follow along and get your dremel out! We can do this. I took EXTENSIVE measurements (like you) and found the CV shaft matches the factory part in every way, except the valley of the splines are just a tad too short (need deeper V)
COVID SUCKS