>From my reading of it the difference is in the two-pinion and
four-pinion diffs, such that "early" axle shafts are 1/32 too long for
later four-pinion diffs, and can give rise to oil leaks at the flanges
due to interference. Part number was not changed from early to late
(thank you Chrysler). Cure is to grind 1/32 from the end of early
shafts OR shim with gaskets OR use later shafts. Bonus for you is that
it appears to affect only the rear axle, since the front drive
couplings take up the 1/32 extra.
Do buy the interchange book before changing the back axle, though, OR
change the complete axle. My WC56 and WC53 run quite happily on the
early axles. I'd like an increase in top speed or better fuel mileage
but what the heck. I'm trying to find an appropriate hood number for
my chassis 81543909 if you can help?
regards, Gordon McMillan, Falkirk, Scotland. 8-)