Thanks for the great suggestions so far! I knew I came to the right place.

--Jay- I appreciate the sanity check on the sprocket fit. Sounds like mine has somehow degraded... Since the damper/pulley only fits over the sprocket and not the crank itself, I can see how this could be the source of my trouble.

Engine seems quite happy otherwise, so as you say, I don't think the bearings are that far gone.

--plh- Yes, the bolt length will be my first check once I get back to the truck (out of town this week). As for the washer direction- It appears symmetrical except for a small chamfer on one side of the inner diameter. Matching the original installation, I oriented this chamfer outward, away from the block. Do you recall if this is correct?

Woodruff key would be worth replacing, it does appear to be seated slightly more deeply into the crank at the end nearer to the block. Any advice on getting it out? Seems pretty stuck. Also, anyone have any info on the part number for that key? Can't seem to find it at the online OEM suppliers.

--Kevin- Definitely will check and compare. It's possible the new damper is off, though since the old one behaved the same I am inclined to give it the benefit of the doubt. Also, since the crank snout does not extend beyond the face of the t-belt sprocket, the damper ID doesn't actually interface with it, only with the bolt. Seems like a strange design choice to me... Or do you think there is something abnormal about my particular truck (a.k.a previous owner did something horrible)?

--John- Thanks, hoping it's not too bad! Though having done the timing belt twice already, I've kinda just resigned myself to doing it again. At least I'm getting quick at it, haha.