You've served me well, but I'm still a little disappointed in you.
TL;DR - The top, military wrap half-leaf on the driver side broke in two places. I'm not sure what I'm going to do as far as replacement goes, but I have two options.
A couple days into the Last Minute Rush trip, I discovered that a new clanking sound from the rear end wasn't something rattling in the bed, but was the military wrap top leaf of my rear springs. It'd broken in two places - at over the rear axle at the u-bolts, and also in the very front where it wrapped around the main leaf. Needless to say, I'd never expected my Alcan springs to fail; I think they did for two reasons. First and most importantly, the leaf wasn't part of the original leaf pack, and in order to make it fit, Alcan didn't wrap it as tightly around the main leaf and front bushing as normal. This allowed it to move more in normal operation, and metal movement leads to fatigue. Secondly - of course - my leaf springs have a lot of miles on them - eventually, failure was inevitable.
As far as what to do - I've already purchased a replacement set of leaf springs from Alcan. The "easy/obvious" solution would be to install them when my new rear axle housing arrives, since I'll be disassembling the rear end anyway. Alternatively, I also still have the original military wrap leafs that came with the springs. I could drill a center hole in the correct place and replace the single leaf. Doing so would allow me to continue to use this pack for another several years, as it's not currently showing any indication of sagging.
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