I first noticed this problem with about 14000 miles on the van. I purchased this vehicle new from a dealer about 120 miles from my home. When I went to rotate the tires I noticed the severe wear on the inside of the rear tires. Since this was the first front wheel drive vehicle i had owned I was monitoring only the front tires to check and see when I should rotate my tires. The outside tread on the rear tires looked good, you had to get on the ground to notice the wearing. I quickly took my vehicle to my hometown GM dealer. They rather abruptly told me there was nothing they could do because I had not rotated my tire at the suggested mileage, 5000 miles. Therefore, I called the dealer I had bought the van from and they gave me the same answer, so did GM themselves. Well I figured the thing just needed a 4 wheel alignment, so I took it to my local alignment shop. They tried but could not get the rear aligned. The owner of the shop called a friend of his at another GM dealership and told him of our problem. The vehicle had not been wrecked, nor had it hit anything to cause this problem. The mechanic at the GM dealer quickly assessed the problem as being a bent axle probably bent during shipment of the vehicle. He stated that often heavy vehicles strapped down on the rear of the haulers can suffer damage if not done properly. So after putting a new set of tires on the van and they began to wear in the same pattern the original dealer decided to replace the rear suspension and axle. This did eliminate the problem, however I was still out of a set of tires and the aggravation of a new vehicle with real problems. I was not a happy camper.