Random thought regarding generating that much heat without rattling ... could a bearing have seized and the bearing itself be spinning in the casing ? ... until it ovaled its seating in the alloy case it would just run like a not very good plain bush.
As TBM says .. maybe something tightened a bit under the Le Mans lap abuse and now it's cooled and loosened with decent lube it may well just run for years ... maybe some increasing test runs keeping an eye on the g/box temp might he in order ... I use one of those cheap laser I/R thermometers for my temp checks but your hand will tell you well enough (if the skin comes off it's probably a bit warm 🙂)
K
