Has anyone experienced a rather sudden occurence if a noisy R&P?

On a trip to Mexico  Copper Canyon, due to a 3 day delay to book the
rail journey with vehicle, I decided to go it over the top.  This was an
all day and into the night journey .  It entailed very very long periods
of 1st and 2nd gear climbs and decents on extremely steep unpaved
logging roads.
The route roughly parallels the rail route which has some 86 tunnels and
36 bridges, so you get some idea of the climbs and decents to cross the
Sierra Madre.

Anyhow, 84 Westy 4 Sp  apx 85K at start and no txmn noise.  At apx 1500
mi after the long climbs/descents the R&P became noticeably noisy.
Fresh oil change was done since the trip also included a rather deep and
long river fording.  No evidence of water,  metal particles removed from
mag plug.

Comlpeted apx 3000 mi trip back to Florida with no noticeable increase
in intensity of R&P noise.

My previous experience with noisy R&P has been that they develop slowly
over an extended period of time.

Could the extended heavy loading of the pinion shim have
overheated/overstressed it  and worn it excessively?

As I replaced the entire txmn with a used one and still have the orig I
am considering a rebuild.  I want to replace the 3/4 hub and have a txmn
I know more about than the used one now running as I plan to keep the
vehicle indefinately.

Any input from anyone who has experienced similar problem most
appreciated.

Harry Patrick
57 Porsche Speedster "Traveler"
80 MB 240D  "Blau Panzer"
84 Westy  "Irish Rover"
88 Rover Vanden Plas "Miz Bucket"

Thanks.