Mister Mike
.......I feel for you Buddy!.......2017 C7 GS 2LT ......answering your plea.....
You mention you replaced the battery.......I did also about a month ago and am still shaking my head because of what that causes to occur ..........BESIDES........the DTC that references that Stabilitrak/rear axle warning
I am still resetting keyless FOB settings and a myriad of other security
settings and locating certain TBIs (trouble codes) that reference the infamous orange MIL light which is what I couldn't get to clear when I replaced battery...IS your MIL LAMP LIT??.....That Malfunctioning Illuminating Lamp(MIL) has about a dozen things that make it light and
worse than that.........some reset themselves
with normal driving (from 0-40driving cycles) and others don't.......The take away here is........You have most probably have "drip dry clutch paks" inside your Tremec transaxle ........Special Mobil 1 rear axle fluid has come out for the sticky thump thump noise you hear....Yours have have gone dry and are sticking.....several 1/2 good fixes of what Iam talking about on You Tube....Secondly cancel your dealership appt....
.....for now......they love desperate people like us and here in Texas...We have a lot of desperados!!!.......I have learned thru 3 Corvettes over 40 years.......GM DEALERSHIPS are useless and a rip off.....I remember the days when they charged you $175.00 to hook up that proprietary computer just for vettes....What a joke...You paid either way and still left with a problem because they couldn't find anything RONG!!....Enuff said......Surprisingly , Your 360 page Owners Manual has a simplistic yet confusing way of showing you HOW TO START OVER by reprogramming all personalization settings etc. which what I had to do.
MY drivers seat was too far to the rear and vette wouldn't accept all the needed info...It probably thought I was crashing and didn't need it because both of my rear 12by20 wheel rims were cracked(another sad story.....Hope this helps....Vaya Con Dios....

 

I took the car to the dealer, they scanned it and said it was a cylinder 8 misfire but they could not get it into service for another 3 weeks! So I decided to try a few things myself. I swapped coil pack 8 with number 2 to see if the problem followed the coil pack but it did not. The code reader still said cylinder 8 misfiring. I really hated to have to pull the fuse box but I don’t think you can get to number 8 plug without doing so, so I pulled it. Dang, what a job! Believe it or not the plug electrode was shorted to ground. Replacing the plug cleared bot the service stabiltrak error and the service rear axle error. It runs smooth now. The only issue is I still have is a check engine light. I’m going to disconnect the battery for a while today to see if the check engine light will go away.

 

Mister Mike…. Go Easy…..You are getting the idea that sometimes what you’re seeing as real problems are “glitches “ or spikes of codes thrown from other modules…The temptation to clear the real from the imagined by dumping the battery is not always the last stab at a remedy..That MIL lamp you’re staring at is possibly counting complete ignition cycles and when you dump the memory…It resets the ignition cycle count….You’ve successfully found and remedied a REAL problem….I would change to new rear end (lower Tremec fluid) gear oil …And then …start reading the 472 TSB’s…that are pertinent to your GS..Some of the bulletins even state there is “no fix” or they are still working on a solution…the infotainment menu display is a perfect example of that..It is not a reinforcing feeling when you can’t even get the the menu sub topics to show up twice in a row!!..I find that with a consumer level diagnostic tool and the DTCs set by the vehicle itself…I’m learning to read the “big picture”…and not always correctly! …Stay Away from Dealer for now.. Relish your success at this stage and remember…”Is this real?..OR..Is this car lying to me!!??!”…

 

Good information and thank you!
I left the negative battery cable off while I mowed the lawn and now the check engine light is off! I had some errands to run so I drove the Vette for about 30 minutes. No other errors or check engine light came on. For now all seems to be ok but it is very frustrating! It will take a couple of weeks for my big hands to heal after the contortions needed to get the number 8 plug off!