my 2018 ss rear end hit 10k miles and the rear end moans on turns when first driven. same with traction control off. any thoughts

 

Hello there. Ron here. I am new to forums and alike but certainly not new to cars. I've been in the business all my life and I just got my medicare card if that tells you anything. Turning wrenches from the early 70's to about 2010, I finally had enough, and today I am in the Coin and Bullion business. Quite a change. No pun intended. Back in the day, working out of a small shop in New Jersey, I had plenty of Get up and go, and built plenty of cars, but my favorite was the shoe box Nova of which I had three. My small block Vega took a close second. These were all daily driver street cars, with which the last Nova saw the track one time back in 1979. This car had a DZ block 302, with 292 castings cyl. heads that were meticulously massaged, topped with a tarantula manifold and 750 dbl pumper, 4 speed rock crusher tranny, and a narrowed 12 bolt with 4:11 gears. It turned low 12's at 115 mph. Not bad for a street car back in the 70's. Today, with computerized fuel injection. variable cam timing, turbos and superchargers, 6 speed transmissions, ( now 8 speed), new cars out of the wrapper are turning 9 seconds. Incredible, and deadly. Now with all that said, I drive a 2018 Camaro 2SS Convertible. My wife says it's a second child hood but I say "Old guys rule". You see, my first car back in 1970 was a second hand 1962 Impala SS blue Convertible. Wish I had that car today! so I thought it only befitting to order a new Camaro in near same description. It's hyper blue with silver rally strips reminiscent of the late 60's. Ordered with magnetic ride and an 8 speed automatic, (I've done my share of shifting gears in traffic and the knees aren't what they used to be). It has Navi and a Kalahari Leather interior with a black ragtop, and 5 spoke silver painted 20's, with runflat tires. This car wasn't cheap. By the time I left the dealership, I dropped 60K. Knowing I had gone in there to buy the Vette instead, which with the same options in a different body would have cost me near 90K. And that was NOT for a Z06. Ridiculous.
So let's talk shop. I see your comment on the diff in your car, and immediately think, "I'll be darned!" I have had my Camaro for 16 months. It is ready near 10K miles and guess what. When back out of my drive in the morning, I hear a moan when turning the wheel and car at a slow roll. But that is not all. Since the day I got this car, I have complained of a vibration coming from the back at exactly 44 mph. It will continue through to 48 mph but lessen the severity as speed increases. At first I was told unable to duplicate. The service writer noted it, but just coming out of a Lincoln Town car, I figured maybe it's me. The 35 series runflats in the back are made out of stone. Their rock hard narrow side walls are not forgiving. I intend to loose them after another 10K. OK...so After another couple thousand miles, I was sure something was wrong. I took it back to the dealer where a tech drove with me and in 30 seconds said he knew the problem. The torque converter clutch was slipping. Really? Did I mention that I was an ASE Certified Master Tech since 1978 and grew up on automatic trans? I didn't necessarily agree with his rapid diag, but hey, things change and I've been out of the circut for a while, so if you feel like replacing the T.C. then be my guest. Bottom line...vibration still there. Back to the dealer later for another free oil change and once again, mention the vibs. This time a road force balance on the rear tires showed that one of the tires/wheels needed to re-indexed. It still shakes. I personally feel there is something going on at the diff. Possible driveshaft, coupler/u-joint, pinion angle? Though this is a stationary diff with half shafts and c.v.'s, could it be internal? Or am I completely off base? Then just recently I joined a gym ( dr reco) I see another Camaro. ss coupe. He likes the car, but hates the vibration. What did you say? Vibration? Here another case at 44mph. Now I see your post. Moaning. Am I seeing a pattern here? I love this car so much that continued putting up with it stead of yelling "Lemon". I've worked dealerships. I can see it coming. A major recall or technical service bulletin. But this may hinder only a few cars for which if it is not a safety hazard, then nothing will be done unless enough people complain.
New technology has got me on this next one. There is a device mounted to the front of the block that regulates an airway from the super large air intake tube and directs it to the interior of the vehicle. Could this device modulate air pressure to cam overlap? How essential is it? I see many cold air set ups have this removed. Any thoughts on the matter would also be appreciated.......

 

Just found a puncture in my run flat. Very slow leak. Dealer tells me I'm down to 5.32's tread depth. Figure that. And with only 10,000 miles!. I do NOT smoke these tires(ok..maybe once), I am tempted to replace the rear tires with something more conventional. My question is this. Can I increase the aspect ratio without headaches? The rear tires are shorter than the fronts. The rears being 35 series and the fronts being 40 series. If I went with a 275/40/20 instead of the 275/35/20, will it create a problem with the ABS or traction control?