Saw something on Scotty Kilmers YouTube where he puts extra heavy duty grease on the cv axle shaft that goes into transmission to make installation of shaft easier. Wondering if that’s safe to do or can it damage your transmission?
To be on the safe side, I would wet the splines with the correct transmission fluid, not grease. But it probably makes no real diff, either way, or no lube at all.
Thick grease helps to keep the retaining clip centered on the stub.