One source that says red loctite for splines:
http://gglotus.org/ggtech/europa-rearaxle/Eurraxle.htm and something different from the Europa Competition manual:
"The rear stub axles were installed using "Loctite Shaft and Bearing Mount" on the threads.
The locking nut was torqued to 160 lbs ft. The hubs should be checked for tightness after every
track session as problems have been experienced with stretching and consequent slackening of
the axle shaft nut. It is recommended that the stub axles be replaced after three practice and race
sessions as a precautionary measure."
I think they meant splines instead of threads, but the text says "threads"
Add to that the callout for sleeve and bearing retainer on the carrier as I knew from the 70s and 80s (along with splines) due to the wear in the press fit of the bearings in the carrier housings ( worn due to multiple bearing fittings over time). So now you have three opinions on what and where from the internet (internet is the greatest thing and the worst thing....). I'm sure there are more.
Now comes Henkel (Loctite Manufacturer) with yet another product -
https://www.henkel-adhesives.com/ee/en/product/retaining-compounds/loctite_660.html It specifically says for splines, worn housings, keyways, etc
Even though I've used the green, Henkel specifically calls out that it is for tight fitting cylindrical applications (think bearings on shafts). These splines are not what I would call tight-fitting even when new.
Historically I agree with BDA, the sleeve and bearing retainer is the better answer for gap filling adn retention in general. Red for threads. But Henkel now says 660 for splines and filling.... anyway, its all best used with primer/activator, especially in gap filling situations (again, per Henkel).
my last .02......
