This clunking noise is one the most common complaints that new Volt owners have, yet somehow it's not the first thing the dealer thinks of. So it could be dealer stupidity, a possibility one should never underestimate. On the other hand, they'd get compensated by GM for providing warranty service for doing the whole axle lube bit, but not (or not as much) for adjusting the bumpers. So it could be dealer fraud, a possibility one should ALSO never underestimate.Thank-you all very much, It was a poor hatchback adjustment. I found the adjustable bumpers (thanks to your feedback) on the r/l of the hatch and extended the right. The noise went away. I have yet to speak to the dealer, but am still dumbfounded that they were going to drill a hole in the axle and spray lub in it for a rattle. Thanks again everyone. I'll start with this forum for any info I need on my car in the future. I love the car and anxious to see in perform in warmer weather.
I suggest you find a different dealer. And if GM sends you a survey about your dealer experience, be sure to be unsparing in your honest assessment.