Yep!!! Boardwalk Chevrolet in Redwood City, CA is the most dishonest dealer EVER. We took our perfectly running Tahoe in for a general tuneup in advance of towing our Airstream 1000 miles. They called and told me they had to replace my rear differential because it was leaking. We parked in the driveway and there was no evidence of a leak so I told them not to do anything and I was sending my husband over after work. He got there and they had already replaced it. He demanded to see the part (CA law that they have to provide your parts if you ask) and they informed him they had already thrown it away. We had to pay $4000. Fast forward to the drive and the truck was running really roughly and it broke down at a rest stop with no cell service. Thank god we were able to sign up for OnStar. I got home, had it out with the dealership, contacted Chevy customer support... no one cared. We vowed NEVER to take our vehicles to the Chevy dealer again, and now that same truck has 260k miles with no issues. It was very clear that they use tuneups to create their own revenue stream.