This relates to my 2022 Stingray, 32,000 miles and now on its fourth transmission.

About 50-miles into the (latest) new transmission, without warning the engine coolant temperature rose in an instant, from around 189-deg to 240-deg and the trans temp rapidly followed from 185-deg to the 210 range and the engine oil temp also rising some 30-degrees as well. Speed was around a constant 50-mph and 1,300 to 1,500 rpm. Both rear fans were running full tilt! Within the next 20-seconds, the engine coolant temp dropped to 190 and the trans and engine oil temps dropped to a more normal range within 30 to 45 seconds. After arriving hope, the coolant reservoir "burped" about a pint of coolant.

Next day, I had to add about a quart of coolant to bring the reservoir to the correct level. Discussed with the dealer and we decided that air in the lines after the trans change was likely the culprit and so onward we went.

Over the next 800 miles or so, there were no major temperature issues although the coolant temp would swing by 10 or 15-degrees for no apparent reason, but things seemed to be settling down.. Until today! Had about a 20-mile run along the freeway - 70 to 80 mph - and then onto a side street for about 3 miles at up to 50 mph when again the temps rose in an instant to 230 on the coolant and 220 on the trans and engine oil. As before, all 3 temps all dropped to around 190 but for the next 5 minutes, all three tracked each other between 190 and 185. A scan after shows no codes or pending codes.

Trying to work out a plan of attack with the dealer but I was wondering if anyone else had seen sudden temperature changes like this?

 

Man you have some serious patience. About the end of the third tranny I’d be taking to a lemon law lawyer. I know that GMs responsibility is to simply remove and replace but you have been put through the wringer. Unless Chevrolet has promised you a gold mine near Las Vegas it’s time they gave you a new car!

 

Don't have that experience with my C8 but it seems like there's still air in the system or the thermostat is acting up. I'd have them change the thermostat and do a proper coolant fill.

 

Wow, 4 transmissions in 32K miles?!

 

You need to purge all the air out of the system. You are intermittently getting coolant, air and steam registering on your coolant temp sender.

 

Good way to damage an engine if it is not already with an air pocket that can cause a lot of damage and localized overheating. They might be replacing the engine next time around.

 

In the GM service manual there is a procedure to bleed the cooling system. It seems this was not done and this is why you are having this issue. What to do? Is it out of place to bring the car back and tell them to follow a procedure they should have done the first time? Or bring to a different dealership, explain the situation and request they run through the bleed procedure? Wherever you go, request they print this procedure out to give you a copy. At least you’ll know they looked at it.

 

Yes, I'm beginning to think replacement is an annual service item!! From my perspective it's poor-to-no quality control. Original trans was a porous case (very visible casting defect); 2nd was a screaming bearing; 3rd was a cracked case that was found during installation.

 

Very poor quality control, and being assembled and having others in the assembly plant who have no mechanical skills doing critical production related jobs. Maybe a temp worker who used to unload box cars installed that failed bearing, and another thought that cracked case didn't matter. CEO's a woman, right? Did she work her way up from the bottom, does she understand any of these things? Not that it matters, but it could, I wanted a C8 since '19, have the cash to buy any one made or even a couple, things like your experience is what's holding me back.

Hoping the best for you from here on out.

 

Do you have a Lemon Law where you are? 4 trannys in 32k miles is unreal.

 

Thats 4 transmissions and counting…..

 

Dealer doesn’t know what the hell there doing!!!
come on?!?!?!
4 transmissions in 30k????? Obviously something else going on.

 

Not sure how it is in your state, but there may be a time/mileage limit on a Lemon Law case. But I agree, four transmissions in 32K miles is total absurd. Hopefully the suggestion on getting the cooling system bled will solve the issue. And maybe find a different dealer to do the work.

 

None of those trans issues were the dealer's fault, 2 faulty cases & a bad bearing

 

One can only imagine how much unseen collateral damage your poor car has suffered after 3 dealer installed transmissions, let alone the overheating syndrome that’s been occurring.

In all seriousness, why are/would you permit this insanity to perpetuate any further?