Here's a link to one of the best posts about diagnosing & fixing DW that I have seen:
Diagnosing Death Wobble and Fixing Non-DW Shimmies and Wobbles
Good reading & explanation and a great pic that is labelled so you are sure about what things are being referred to.
As Mobbzy mentioned. The bolt holes are a bit bigger than the bolts. This is due to Jeep drilling imperial holes then using slightly undersized metric bolts...
I suspect someone there used to work at NASA on the Mars probes...