so i take the car to the dealer for the rear diff growling i get once the car warms up. they add the recommended 4 oz of friction lube. they drive it and it is still there. they say they will talk to tech, but possibly the clutches need replaced. i also got the first free oil change at the same time. i drive the car home, but make some turns and the sound is going away. i take it for a 15 min ride, then do some more turns and great no noise, it is fixed. i get home and there is a message on the machine saying that tech says the noise is normal, because i have high perf/racing rearend. oh well it is fixed. i get the paperwork in the mail the next day, saying just that. i notice they put in 8 quarts of oil, i check the car and it is a quarter inch over the high circle on the dipstick. i grab my manual (gt500 supplement) and i see it takes 6.5 quarts, and it says to use the 4oz friction modifier. anyways i go back to the dealer and drop both of these bombs on the service guy. i basically tell him i am not too happy with their service, while showing him in the manual what the car is supposed to have. well they fix the overserviced engine oil, and hopefully make a mental note of both problems for the next guy with a gt500. then they apoligize and try to send me on my way. i'm like you must be kidding. i want paperwork saying you overfilled the oil and you removed said oil. so i do get that it states. customer states engine oil over filled from last service, verified concern found 1 quart over filled. drain oil to correct spec. so i won't be going there for service anymore, just very dissapointing.

Everytime I take mine in I remind them about the spec for the oil. Did they use the 5W50 in yours? Probably worth checking your slip, if they don't know how much oil they might not know which oil either.
Eric

yeah they used the correct oil. i change my own oil in my cars, but figured it hit them up on the first free one.

Wow that sucks that free oil change probably ended up costing you more in gas and time wasted going back to the dealer plus knowing it was overfilled so glad you caught it.