[DirtyLarry]

Well, heck…I got my bearings totally backwards somehow. Positive caster would be tilting the pinion down (upper balljoint/kingpin tilted towards the back which would mean the pinion would have to come down). Too many years away from alignments I guess. Sorry…

Hopefully correcting the toe corrects the issue. For some reason the axle position (diff-cover view) still seems off kilter to me but I could be wrong.

I just looked up the toe settings for a 1999 3500-HD with an I-beam front axle and it is 0.028 degrees-0.028 degrees while a late model GM 4500 4x4 with a SFA calls for the toe to be 0.02-0.08° and a caster setting of 3-5°.

It looks like you have a Ford Dana 60 so it would be worth checking the specs for a F-truck, which you probably already have done.

Sorry to confuse you with my previous backasswards post.