Andrey, sounds like the exact problem (shock and dealer) that I had. I knew my right rear shock was bad, a lot of bouncing, noise, etc. Had the dealer inspect it, test drove it with mechanic and service guy, nothings wrong, come back if it gets worse. Man was I pissed. I was about to go to another dealer, but I took both rear shocks off, the good one immediately extended to full length and was very difficult to compress, the bad one wouldnt extend and moved up and done easily. There was no visible leakage, but you could shake it and hear a noise. Took both loose shocks to the dealer, the tech said, oh well, we dont get paid to remove the shocks to inspect them. The service advisor appologized and said I should have never had to do that. Oh well, got the one bad one replaced. My front one was easier to convince the service tech, by using the bounce test (didnt work well for the rea - maybe because of the solid axle). This was after they told me there was nothing wrong, since the dash didnt display a warning or service light. They tried to tell me I had electronic suspension....boy did I lay into them on that one, idiots!!!
Mike Skurich
1969 C3 Corvette Coupe
1988 C4 Corvette Coupe
1992 Misubishi 3000GT VR4
1997 BMW F650ST
2001 VehiCROSS
2002 BMW R1100S
2005 C6 Corvette Coupe