Good news: Took my GTO to the dealer this morning for its 4000-mile oil change. They sent me a coupon a while back, so I got the whole service for $15.95 and that's with Mobile1 oil. Can't beat that with a stick. Also asked the tech to check for any leaks anywhere while he had the car on the lift, he said it's dry as a bone.
More good news: Just finished changing the rear differential fluid to RP Maxgear 75-140. Easy job, 30 minutes tops. Only spilled a few drops.
Bad news: It started raining just as I finished up, and I don't want to get my freshly washed and waxed car out in the rain, so I'll probably have to wait till tomorrow to see if I can tell any difference after the rear end fluid change.
Thanks again to everyone for the help and info!
