crheming

I have had my truck in the shop for over a month. Road forced the stock goodyears twice (didn't help), got new goodyear all terrain adventures w/ kevlar (my favorite tire, have had on multiple trucks - didn't help), replaced one of the new tires that was slightly out of spec (didn't help), road forced again (didn't help), GM engineering sent my dealership this fancy vibration analysis device. They took apart my front diff and replaced the ring gear (4x4 vibration that I honestly didn't even notice but the shop foreman did) and put new Michelin LTX MS2 on it (for the high speed vibration), road forced, and voila, it's fixed!! They had the Goodyear rep at the dealer over this as well, and he said that TONS of sierras are having problems with Goodyears (especially the Z-71s with 20s on them).